Strap size by lug width
21 mm lug width watches
3 watches in our base take a 21 mm strap (2 Citizen, 1 Seiko), with cases of 38–42 mm and 45.9 mm lug to lug. To check your own, measure the gap between the lugs, inside edge to inside edge: that is the lug width, and the strap and its spring bars must be that wide.
Watches with 21 mm lugs
Each lug width below comes from a cited source; the model page has every size. Integrated bracelets and proprietary straps are not listed: they take no standard strap.
Silhouettes from the published sizes, shortest first, all to one scale; the bar and each grid square are 10 mm. Not photos.
Show the specs table · 3 models, every number with its source
- Citizen Stiletto AR3075-51E
Stiletto · Citizen G870
- Citizen ATTESA AT8294-59E
ATTESA · Citizen H800 (Eco-Drive, radio-controlled) · quartz (analog)
- Seiko SSC957
Prospex · movement not published
Measuring and choosing a 21 mm strap
- How to measure lug width
- Strap off, calipers or a ruler across the gap between the two lugs on one side, inside edge to inside edge, read in millimetres: a 21 mm gap takes a 21 mm strap.
- Strap and spring bars
- 21 mm wide at the lug end, on spring bars for a 21 mm gap. The bar tips must also fit the holes in the lugs (1.8 mm is the usual size; thinner and thicker exist).
- Case thickness here
- 4.7–13 mm
- Wrists that suit them
- balanced from ~16 cm (shortest, 45.9 mm) to ~16 cm (longest, 45.9 mm); flat-fit estimate
A 20 mm strap leaves a visible gap between the lugs and a 22 mm one has to be forced in, so buy the exact width. The figures above are the ranges of the 3 models listed here, not a rule for every 21 mm watch. Work out your strap length in the watch strap size tool.
21 mm lug width questions
Which watches have a 21 mm lug width?
Citizen: AR3075, AT8294. Seiko: SSC957. That is 3 models in our base with a sourced 21 mm lug width.
How do I measure the lug width of my watch?
Take the strap off, then measure the gap between the two lugs on one side, from the inside edge of one lug to the inside edge of the other, with calipers or a ruler on a flat surface. That gap in millimetres is the lug width, and the strap you buy must be that wide at its lug end. If the strap is still on, measure the strap itself where it meets the case.
What spring bars does a 21 mm strap need?
Spring bars for a 21 mm gap are 21 mm long, shoulder to shoulder; the bar compresses to slip in between the lugs. Their tips must also match the holes in your lugs: 1.8 mm is the usual tip size, and thinner and thicker ones exist, so if a bar does not seat, check the hole before forcing it.
Can I put a 20 mm or a 22 mm strap on a 21 mm watch?
A 20 mm strap leaves a visible gap beside each lug, and a 22 mm one has to be forced in and can mark the lugs. Buy the exact width.
Sources
Documents checked · Report a wrong number
- 1Citizen Watch US — Stiletto - Men's Eco-Drive AR3075-51E Sleek Black Steel Watch · html · read
- 2Citizen Watch US — ATTESA Black Dial Super Titanium with DLC Coating Bracelet AT8294-59E · html · read
- 3Seiko Watch Corporation — SSC957 product page (Prospex), seikowatches.com global-en · html · read