Withings ScanWatch 2 Strap Size: The Complete Reference

The Withings ScanWatch 2 comes in two case sizes, and each takes a different strap width: the 38 mm case uses an 18 mm strap, while the 42 mm case uses a 20 mm strap. Both widths use ordinary quick-release spring bars, so your buying decision is straightforward once you know which case is on your wrist.

3 Key Takeaways: Withings ScanWatch 2 Strap Size

• Two sizes: The 38mm ScanWatch 2 takes 18mm straps. The 42mm takes 20mm.

• Not interchangeable: An 18mm strap won't fit the 42mm case, and a 20mm strap won't fit the 38mm.

• Standard quick release: Both use regular spring bars, so any matching-width strap fits.

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 confirm the same specification.

Table of Contents

• What Strap Size Does the Withings ScanWatch 2 Take
• Which ScanWatch 2 Case Size Do You Own
• How to Measure Your Wrist for a ScanWatch 2 Strap
• Which Closure Style Fits How You Wear It
  • Magnetic Milanese for fine adjustment
  • Pin buckle for dependable retention
  • Silicone and nylon for active use
• Why Quick-Release Spring Bars Matter on the ScanWatch 2
  • A careful swapping sequence
• Do ScanWatch Light Nova and Steel HR Use the Same Width
• ScanWatch 2 Strap Compatibility Checklist
• Where to Find ScanWatch 2 Replacement Straps
• Frequently Asked Questions About ScanWatch 2 Straps
  • Will an 18 mm strap fit the 42 mm ScanWatch 2?
  • Can you use a third-party strap on the ScanWatch 2?
  • Does strap material affect the ScanWatch 2 sensors?
  • Are ScanWatch 2 straps compatible with every Withings watch?

What Strap Size Does the Withings ScanWatch 2 Take

The decision is fixed: 38 mm means an 18 mm strap, and 42 mm means a 20 mm strap. These widths are not interchangeable, so identify the watch case before comparing materials, colours, closures, or lengths.

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 straps without relying on a brand-specific connector. Browse a collection of compatible ScanWatch 2 straps after confirming the case size.

The supplied strap's finish does not change the fit. Fluoroelastomer, Milanese mesh, silicone, nylon loop, and leather-style straps 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 strap will not seat correctly on the 42 mm case, and a 20 mm strap 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 strap.
• ScanWatch 2 42 mm: search for a 20 mm strap.

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.

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 strap.
• 42 mm case: Choose a 20 mm replacement strap.

For an 18 mm ScanWatch 2, the Rovan Magnetic Silicone Sport Strap 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 Strap

The lug width decides whether a strap 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 strap 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 strap, 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 strap. 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 strap, but the width still has to match the ScanWatch 2 case.

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 strap 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 strap a fixed closing point and keeps the watch from sliding when you move. Leather-style, canvas, and similar buckle straps 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 strap with a thumbnail instead of a tool, which is especially valuable on a polished stainless-steel case. The correct replacement strap 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 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 strap 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 strap 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 strap gently in both directions. The spring-bar ends should sit fully inside the lug holes.

The quick-release watch strap guide 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 strap for the 38 mm case and a 20 mm strap 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 strap 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 straps, and the 42 mm case uses 20 mm straps. Withings publishes a wristband width for each of the sibling models too, and they don't all land on the same number.

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 strap 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 Strap Compatibility Checklist

A compatible Withings ScanWatch 2 replacement strap must match the case width first, then the spring-bar format and the wearer's fit. Use the checklist below before buying.

1. Strap 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 strap end should sit neatly between the lugs without rattling or forcing. A narrow strap leaves a visible side gap, while an oversized strap 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.

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 Straps

Start with the case size, not the material. Choose the 18 mm quick-release strap range for a 38 mm ScanWatch 2 and the 20 mm quick-release strap range for a 42 mm ScanWatch 2. Nothing But Bands ' Withings ScanWatch straps collection is organized around replacement options for this family, while separate width collections let you narrow the search further.

The 18mm quick-release straps are the correct starting point for the 38 mm ScanWatch 2. The 20mm quick-release straps are the correct starting point for the 42 mm version.

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 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 Straps

Will an 18 mm strap fit the 42 mm ScanWatch 2?

No. The 42 mm ScanWatch 2 requires a 20 mm strap, 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 strap on the ScanWatch 2?

Yes. The ScanWatch 2 uses standard quick-release sizing, so a third-party strap 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 strap material affect the ScanWatch 2 sensors?

The strap 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 straps compatible with every Withings watch?

No. Withings publishes a width per model: the ScanWatch Light takes an 18 mm strap, the ScanWatch Nova a 20 mm strap, and the Steel HR 18 mm or 20 mm depending on whether it's the 36 mm or 40 mm case. A ScanWatch 2 strap 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 straps in 18 mm and 20 mm, covering both Withings ScanWatch 2 case sizes without implying they are Withings-branded accessories. Visit Nothing But Bands after confirming your case size, then choose the width and closure that match the way you wear your watch.