Watch Lug Width Chart — G-Shock, Seiko & Apple Watch
Most watch mods come down to one number: your lug width — the gap between the lugs where the strap attaches. Measure it once, match it to this chart, and every strap you ever buy fits.
Rule of thumb: measure between the lugs in millimeters — that number is your strap width. A 22mm strap never fits a 20mm watch, and vice versa.
The chart
| Watch | Lug width | Adapter needed? | Notes |
|---|---|---|---|
| GA-2100 / GA-2110 (CasiOak) | Proprietary mount — no standard width | Yes — 22mm adapter | Resin lugs take only the stock band until an adapter converts them to spring bars |
| GA-B2100 | Proprietary mount | Yes — adapter per listing | Check the listing’s compatibility line before ordering |
| DW-5600 / DW-5610 / GW-M5610 (square) | Integrated band | Yes — 16mm adapter | Adapter converts the square family to standard spring bars |
| F-91W / A158 / A159 | 18mm | No | Standard spring bars — direct swap in minutes |
| AE-1200 / AE-1300 (Royale) | 18mm | No | Standard 18mm spring bars — the stock strap is 21mm wide at the case, order 18mm replacements |
| MDV-106 / MDV-107 (Duro) | 22mm | No | Dive-grade bracelets and rubber both direct-fit |
| SKX007 / SKX009 / SKX173 | 22mm | No | The most strap-swapped watch ever made |
| SKX013 (mid-size) | 20mm | No | The #1 SKX013 mistake: ordering 22mm |
| SRPD / Seiko 5 Sports | 22mm | No | Straight end links sit cleanest |
| Turtle / Sumo | 22mm | No | Curved-end straps match the case silhouette |
| Alpinist | 20mm | No | Leather is the traditional pairing |
| Apple Watch | Band slot by case size | No | Small 38/40/41mm · Large 42/44/45/46mm · Ultra 49mm (takes Large bands) |
How to measure in 5 seconds
Put a ruler across the gap between the lugs — the distance in mm is your strap width. On Apple Watch, read the case size engraved on the sensor crystal instead.
Width vs taper
Two-piece straps taper — a 22mm bracelet tapers to 20mm at the buckle, which is normal. One-piece straps (NATO, Zulu, Perlon) run the same width end to end and thread under the watch.
Casio digital & dress models — full size reference
Band width and spring-bar width are not the same number: the AE-1200’s stock strap is 21mm wide where it meets the case, but it mounts on 18mm bars. Screen sizes (width × height) matter for case kits and screen protectors.
| Model | Lug (spring-bar) width | Strap width at case | Screen (W×H) |
|---|---|---|---|
| F-91 series | 18mm | — | 12×22mm |
| A158WA-1 | 18mm | — | 12×22mm |
| A168WA-1 | 18mm | — | 12×22mm |
| A159WA / A159W | 18mm | — | 12×22mm |
| A168WEM series | 18mm | — | 22×12mm |
| AE-1200 | 18mm | 21mm | 24×24mm |
| AE-1300 | 18mm | 21mm | 24×24mm |
| AEQ-110W-1B | 18mm | 21mm | — |
| W-S200H | 18mm | 21mm | — |
| W-800 / W-800H | 18mm | 21mm | — |
| W-216 / W-218 | 18mm | 21mm | 21×18mm (W-218) |
| AE-1500WH-1A | 18mm | 28mm outer | — |
| DW-5600 series | 16mm | — | 21×18mm |
| DW-5600SK-1P | 16mm | — | 24×17mm |
| LA680WA-1 | 13mm | — | 15×12mm |
| MQ-24 series | 16mm | — | — |
| WS-1400H-1B | 18mm | — | — |
| MDV-106 (Duro) | 22mm | — | — |
| MDV-10D-1A (small Duro) | 16mm | — | — |
| MWA-100HD-1A | 20mm | — | — |
| MTP-VD01D series | 22mm | — | — |
| MTP-VD300D-1E | 22mm | — | — |
| MTP-1384D-1A | 22mm | — | — |
| MTP-VT01L-1B | 20mm | — | — |
| MTP-V004L-7A | 20mm | — | — |
| MTP-1375L | 18mm | — | — |
| LTP-VT01L-1B | 16mm | — | — |
| LTP-1391 series | 14mm | — | — |
| LTP-1314 series | 15mm | — | — |
| LTP-A009D series | 9mm | — | — |
| LTP-1177A-2A | 13mm | — | — |
| LTP-A007 (flat-end) | 14mm | — | — |
| LTP-1241 (recessed-end) | 14mm | — | — |
| LTP-1183A | 14mm | — | — |
| LTP-V005GL | 14mm | — | — |
| Armani-compatible dress series | 14mm | — | — |
Reference: supplier fitment data, October 2026. When your model isn’t listed, measure the spring-bar gap — that number wins over any chart.
Shop by width
- GA-2100 adapters (convert to 22mm)
- Square DW-5600 adapters (convert to 16mm)
- SKX straps (22mm) · Duro straps (22mm) · F-91W straps (18mm) · AE-1200 straps (18mm)
- Apple Watch Large bands · Small bands
FAQ
Is strap width the same as case size?
No — case size is the watch’s diameter (e.g. 44mm); strap width is the gap between the lugs (e.g. 22mm). They are different numbers on the same watch.
What if my watch isn’t in the chart?
Measure the lug gap in mm. Any two-piece strap of that exact width fits a watch with standard drilled lugs — no adapter needed.
Why is the AE-1200 strap 21mm wide but called 18mm?
Width at the case and spring-bar width differ: the stock strap measures 21mm wide where it meets the case, but it mounts on 18mm bars — order 18mm replacements.
Do GA-2100 straps fit without an adapter?
No. The CasiOak’s resin lugs take only the stock band; a 22mm adapter converts the mount in about five minutes. See our adapter install guide.
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