**By Alex** · 2026-09-03 The Withings ScanWatch 2 comes in two case sizes, and each takes a different band width: the **38 mm case uses an 18 mm band**, while the **42 mm case uses a 20 mm band**. Both widths use ordinary quick-release spring bars, so your buying decision is straightforward once you know which case is on your wrist. The catch is that **18 mm and 20 mm aren't interchangeable**. An 18 mm strap belongs on the 38 mm ScanWatch 2, and a 20 mm strap belongs on the 42 mm version. The width is the first filter, before material, colour, closure, or strap length. Withings publishes these two pairings in its ScanWatch 2 dimensions and materials guidance, and its [wristband-changing instructions](https://support.withings.com/hc/en-us/articles/17091499862033-ScanWatch-2-Changing-the-wristband) confirm the same specification. ## Table of Contents - [What Band Size Does the Withings ScanWatch 2 Take](#what-band-size-does-the-withings-scanwatch-2-take) - [Which ScanWatch 2 Case Size Do You Own](#which-scanwatch-2-case-size-do-you-own) - [How to Measure Your Wrist for a ScanWatch 2 Band](#how-to-measure-your-wrist-for-a-scanwatch-2-band) - [Which Closure Style Fits How You Wear It](#which-closure-style-fits-how-you-wear-it) - [Magnetic Milanese for fine adjustment](#magnetic-milanese-for-fine-adjustment) - [Pin buckle for dependable retention](#pin-buckle-for-dependable-retention) - [Silicone and nylon for active use](#silicone-and-nylon-for-active-use) - [Why Quick-Release Spring Bars Matter on the ScanWatch 2](#why-quick-release-spring-bars-matter-on-the-scanwatch-2) - [A careful swapping sequence](#a-careful-swapping-sequence) - [Do ScanWatch Light Nova and Steel HR Use the Same Width](#do-scanwatch-light-nova-and-steel-hr-use-the-same-width) - [ScanWatch 2 Band Compatibility Checklist](#scanwatch-2-band-compatibility-checklist) - [Where to Find ScanWatch 2 Replacement Bands](#where-to-find-scanwatch-2-replacement-bands) - [Frequently Asked Questions About ScanWatch 2 Bands](#frequently-asked-questions-about-scanwatch-2-bands) - [Will an 18 mm band fit the 42 mm ScanWatch 2?](#will-an-18-mm-band-fit-the-42-mm-scanwatch-2) - [Can you use a third-party band on the ScanWatch 2?](#can-you-use-a-third-party-band-on-the-scanwatch-2) - [Does band material affect the ScanWatch 2 sensors?](#does-band-material-affect-the-scanwatch-2-sensors) - [Are ScanWatch 2 bands compatible with every Withings watch?](#are-scanwatch-2-bands-compatible-with-every-withings-watch) ## What Band Size Does the Withings ScanWatch 2 Take The decision is fixed: **38 mm means an 18 mm band**, and **42 mm means a 20 mm band**. These widths are not interchangeable, so identify the watch case before comparing materials, colours, closures, or lengths. Case Size Band Width Stock Strap ScanWatch 2 38 mm **18 mm** Matching quick-release fluoroelastomer band ScanWatch 2 42 mm **20 mm** Matching quick-release fluoroelastomer band Withings offers the ScanWatch 2 in these two case sizes, each with its corresponding **18 mm or 20 mm wristband width**. Both use standard quick-release spring bars, so you can choose compatible replacement bands without relying on a brand-specific connector. Browse [a collection of compatible ScanWatch 2 bands](https://nothingbutbands.com/collections/withings-scanwatch-bands) after confirming the case size. The supplied strap's finish does not change the fit. Fluoroelastomer, Milanese mesh, silicone, nylon loop, and leather-style bands all need the correct lug width. A different strap material is fine. A different width is not. > **Buying rule:** Identify the case first, then buy the matching width. Choose the material and closure after that. An **18 mm band** will not seat correctly on the 42 mm case, and a **20 mm band** will not fit the 38 mm case. Use the case-size pairing as your filter when searching: - **ScanWatch 2 38 mm:** search for an **18 mm band**. - **ScanWatch 2 42 mm:** search for a **20 mm band**. This single check prevents the common ordering mistake. Confirm the number on the watch before opening a product listing. ## Which ScanWatch 2 Case Size Do You Own The **38 mm Withings ScanWatch 2 has an 18 mm lug gap**, while the **42 mm Withings ScanWatch 2 has a 20 mm lug gap**. Measure the inner distance between the lugs with a ruler, or check the case-back marking if you can't measure the watch comfortably. Turn the watch over and measure the gap where the strap ends sit. Read the space between the inside faces of the lugs, not the outside width of the case. An **18 mm reading identifies the 38 mm version**, while a **20 mm reading identifies the 42 mm version**, matching Withings' published sizing. ![A guide showing three methods to determine the correct case size for a Withings ScanWatch 2.](https://cdnimg.co/4d55836e-96bd-4fa5-a561-7b8375758412/e78c7e1d-c0a0-4c53-a4ba-a32b3feee09c/withings-scanwatch-2-band-size-watch-sizing.jpg) If measuring is awkward, inspect the case back for the engraved case-size information. Use the number shown there rather than guessing from how large the watch looks on your wrist. A visual comparison can help, but it shouldn't override the lug measurement or case-back marking. Use the match below before opening a product listing: - **38 mm case:** Choose an **18 mm** replacement band. - **42 mm case:** Choose a **20 mm** replacement band. For an 18 mm ScanWatch 2, the [Rovan Magnetic Silicone Sport Band Quick Release 18mm](https://nothingbutbands.com/products/rovan-silicone-sport-band-quick-release-18mm) is specified for watches with 18 mm quick-release lugs. Its silicone construction is suited to sweaty or wet use, and its quick-release pins allow tool-free swapping. ## How to Measure Your Wrist for a ScanWatch 2 Band The **lug width decides whether a band fits the watch**, while wrist circumference decides whether the strap length fits you. Wrap a soft tape around the wrist just above the wrist bone, where the ScanWatch 2 normally sits, and record the circumference in millimeters without pulling the tape tight. Withings gives wrist-fit ranges of **146 mm to 211 mm for the 38 mm model** and **163 mm to 239 mm for the 42 mm model** in its wearing guidance. Those ranges show why the supplied band length and notch placement matter, especially if your wrist sits near the lower or upper end of the supported fit. Before buying a third-party band, check its stated wrist range. Match that range to your own measurement, then consider how the closure adjusts. A pin buckle offers fixed holes, while Milanese mesh gives continuous adjustment. Silicone and nylon are usually easier to fine-tune across changing wrist conditions than a rigid bracelet. For a compact explanation of wrist circumference measurement, use this [guide to measuring your wrist for a watch band](https://nothingbutbands.com/blogs/news/how-to-measure-wrist-for-watch). Keep this step separate from measuring the lug gap. Wrist circumference helps you choose the length, but it can't tell you whether the watch needs 18 mm or 20 mm. ## Which Closure Style Fits How You Wear It A **magnetic Milanese closure suits dressier, adjustable wear**, a **pin buckle is the secure default for sport and sleep**, and **silicone is the practical choice for training**. Nylon works well when you want a light, breathable everyday band, but the width still has to match the ScanWatch 2 case. Closure Best For Avoid If Magnetic Milanese Office wear, dressier outfits, stepless adjustment You want maximum grip during vigorous movement Pin buckle Sport, sleep tracking, dependable retention You need continuous adjustment without buckle holes Silicone Training, sweat, water exposure, easy cleaning You prefer a formal metal appearance Nylon loop Breathable everyday wear and casual rotation You need a more structured, dress-oriented finish ### Magnetic Milanese for fine adjustment Milanese mesh is the strongest option when comfort depends on small adjustments. The magnetic clasp lets you loosen or tighten the band without committing to preset buckle holes, which is useful when your wrist changes slightly during the day. It also gives the hybrid ScanWatch 2 a more polished appearance under a shirt cuff. The trade-off is security. A magnetic closure can move more readily than a properly fastened pin buckle during demanding activity, so I wouldn't make it the first choice for running or overnight wear if the watch tends to shift on your wrist. ### Pin buckle for dependable retention A traditional pin buckle is the sensible choice for **sport and sleep tracking**. It gives the band a fixed closing point and keeps the watch from sliding when you move. Leather-style, canvas, and similar buckle bands also sit neatly against the case back and work well in casual or formal rotation. ### Silicone and nylon for active use Silicone is the clear training choice. It handles sweat and water, wipes clean easily, and grips the wrist more consistently than a smooth metal mesh. Nylon is lighter and breathable, making it useful for warm-weather everyday wear, but it can retain moisture longer than silicone. Eric Martinez described the Solin Magnetic Milanese in 20mm this way: “Totally worth the price—this magnetic Milanese is stylish and super easy to switch out. Feels solid and looks great, like a good deal all around.” ## Why Quick-Release Spring Bars Matter on the ScanWatch 2 Quick-release spring bars let you change a **Withings ScanWatch 2 band with a thumbnail instead of a tool**, which is especially valuable on a polished stainless-steel case. The correct replacement band should include compatible quick-release hardware in the appropriate width. Don't force a standard tool between the strap and a polished lug unless you know exactly what you're doing. A slipping fork can mark the finish, while a rushed removal can scratch the lug edge. Quick-release hardware reduces both problems by keeping the removal point on the strap side. ![A graphic explaining the benefits of quick-release spring bars for changing watch bands without any tools.](https://cdnimg.co/4d55836e-96bd-4fa5-a561-7b8375758412/56a86343-4605-4fce-84d5-49d42ffa9de6/withings-scanwatch-2-band-size-spring-bars.jpg) ### A careful swapping sequence 1. **Protect the case.** Place the watch face-down on a soft, clean cloth, with the lug openings easy to see. 2. **Release one side.** Slide the spring-bar lever inward with your fingernail. If the band doesn't have a lever, use a forked spring-bar tool carefully from the rear. 3. **Ease out the bar.** Let one end clear the lug before removing the band completely. Don't twist the tool against the polished metal. 4. **Repeat on the other side.** Keep the spring bar controlled so it doesn't disappear into carpet or fall onto a hard surface. 5. **Install the replacement.** Seat one end in its lug hole, compress the lever, and align the opposite end before releasing it. 6. **Check the lock.** Pull the band gently in both directions. The spring-bar ends should sit fully inside the lug holes. The [quick-release watch strap guide](https://nothingbutbands.com/blogs/news/quick-release-watch-strap) covers the same tool-free approach in more detail. Watch the movement before trying the swap, and stop if the bar doesn't release smoothly. The width remains the most important part. Use an **18 mm band for the 38 mm case** and a **20 mm band for the 42 mm case**. A quick-release mechanism makes installation easier, but it can't compensate for the wrong lug width. ## Do ScanWatch Light Nova and Steel HR Use the Same Width The **ScanWatch Light, ScanWatch Nova, and older Steel HR don't all take the same band width as the ScanWatch 2**. The Withings family includes visually similar watches in different case sizes, so buying by the word “ScanWatch” alone is unreliable, each model splits between 18 mm and 20 mm on its own case dimensions, not the ScanWatch 2's. For the ScanWatch 2, the published pairing is clear: the 38 mm case uses 18 mm bands, and the 42 mm case uses 20 mm bands. Withings publishes a wristband width for each of the sibling models too, and they don't all land on the same number. Model Case Size Band Width ScanWatch 2 38 mm 18 mm ScanWatch 2 42 mm 20 mm ScanWatch Light 37 mm 18 mm ScanWatch Nova 42 mm 20 mm Steel HR 36 mm 18 mm Steel HR / Steel HR Sport 40 mm 20 mm Those widths come from Withings' own dimension pages for the ScanWatch Light and the Steel HR and Steel HR Sport; the ScanWatch Nova is sold in a single 42 mm case and takes a 20 mm wristband. The practical advice is unchanged: **don't buy a ScanWatch Light, ScanWatch Nova, or Steel HR replacement using the ScanWatch 2 number alone** — read the width Withings publishes for the model you actually own. Check the model name and case-back marking before ordering. A band listing that names a different Withings model isn't automatically compatible just because the watch looks similar or the advertised width appears familiar. ## ScanWatch 2 Band Compatibility Checklist A compatible **Withings ScanWatch 2 replacement band must match the case width first**, then the spring-bar format and the wearer's fit. Use the checklist below before buying. 1. **Band width:** Select **18 mm for the 38 mm case** or **20 mm for the 42 mm case**. These are separate choices, not interchangeable sizes. 2. **Spring-bar type:** Look for quick-release spring bars if you want tool-free changes. The ScanWatch 2 uses standard quick-release sizing, so the listing should identify the correct width clearly. 3. **Lug-gap fit:** The band end should sit neatly between the lugs without rattling or forcing. A narrow band leaves a visible side gap, while an oversized band won't seat properly. 4. **Closure:** Choose magnetic Milanese for stepless adjustment and a dressier look, pin buckle for secure sport or sleep wear, and silicone for training. 5. **Wrist fit:** Compare the product's stated strap range with your measured circumference. The strap needs enough usable tail for the closure to sit securely, not merely enough length to reach around the wrist. ![A checklist infographic outlining five essential factors for selecting compatible bands for the Withings ScanWatch 2.](https://cdnimg.co/4d55836e-96bd-4fa5-a561-7b8375758412/25e2f5f0-1137-4eb8-a75f-fb4628f6a3e8/withings-scanwatch-2-band-size-compatibility-checklist.jpg) Don't let a product title do all the work. Confirm that the listing names the **18 mm or 20 mm width**, specifies quick-release hardware if that's what you want, and provides a wrist-fit range. Those three checks remove most ordering mistakes before checkout. ## Where to Find ScanWatch 2 Replacement Bands Start with the case size, not the material. Choose the **18 mm quick-release band range for a 38 mm ScanWatch 2** and the **20 mm quick-release band range for a 42 mm ScanWatch 2**. Nothing But Bands' [Withings ScanWatch bands](https://nothingbutbands.com/collections/withings-scanwatch-bands) collection is organized around replacement options for this family, while separate width collections let you narrow the search further. The [18mm quick-release bands](https://nothingbutbands.com/collections/18mm-watch-bands) are the correct starting point for the 38 mm ScanWatch 2. The [20mm quick-release bands](https://nothingbutbands.com/collections/20mm-watch-bands) are the correct starting point for the 42 mm version. ![Replacement watch bands suitable for the Withings ScanWatch 2 in 18 mm and 20 mm widths.](https://cdnimg.co/4d55836e-96bd-4fa5-a561-7b8375758412/a4280028-eea6-4f52-b8dd-a8857628c703/withings-scanwatch-2-band-size-watch-bands.jpg) From there, match the style to your routine. Silicone makes sense for training and water exposure, Milanese mesh offers a dressier adjustable finish, and nylon provides a lighter everyday option. Product pages should also give you the strap's fit range and closure details, which are the next facts to check after width. The [Solin Magnetic Milanese in 20mm](https://nothingbutbands.com/products/solin-magnetic-milanese-quick-release-20mm) is a suitable width option for the 42 mm ScanWatch 2 because it uses a 20 mm quick-release format. It isn't the right choice for the 38 mm case, regardless of its closure or appearance. ## Frequently Asked Questions About ScanWatch 2 Bands ### Will an 18 mm band fit the 42 mm ScanWatch 2? No. The **42 mm ScanWatch 2 requires a 20 mm band**, so an 18 mm strap is the wrong width. It may leave a side gap and fail to sit securely between the lugs. ### Can you use a third-party band on the ScanWatch 2? Yes. The ScanWatch 2 uses standard quick-release sizing, so a third-party band can fit when its width matches the case. Choose 18 mm for the 38 mm model and 20 mm for the 42 mm model, then confirm the strap length suits your wrist. ### Does band material affect the ScanWatch 2 sensors? The band material doesn't determine whether the watch's sensors can operate. The important fit issue is keeping the watch secure and positioned correctly against the wrist, with the case-back sensor area unobstructed. ### Are ScanWatch 2 bands compatible with every Withings watch? No. Withings publishes a width per model: the ScanWatch Light takes an 18 mm band, the ScanWatch Nova a 20 mm band, and the Steel HR 18 mm or 20 mm depending on whether it's the 36 mm or 40 mm case. A ScanWatch 2 band carries over only where the published width happens to match, so check the model before reusing or ordering. * * * Nothing But Bands offers universal quick-release bands in **18 mm and 20 mm**, covering both Withings ScanWatch 2 case sizes without implying they are Withings-branded accessories. Visit [Nothing But Bands](https://nothingbutbands.com) after confirming your case size, then choose the width and closure that match the way you wear your watch. **Tags:** 18mm watch bands, 20mm watch bands, quick release watch straps, scanwatch 2 bands, withings replacement bands --- > Source: [Nothing but Bands](https://nothingbutbands.com/blogs/news/withings-scanwatch-2-band-size)