The Shell Cordovan Strap. Double-Sided Horsehide. Black.
Shell cordovan is the most prized leather in the trade — cut from the dense fibre layer of a horse's hindquarter, where the grain packs so tightly the surface takes on a deep, glassy shine. Ours comes from the Shinki Hikaku (新喜皮革) tannery in Japan, the name behind the most uniform, immaculate cordovan made — and it is likely to outlast the watch it's on.
We build every cordovan strap double-sided: shell cordovan for the lining as well as the face, where most makers save cost with a cheaper backing. Cut, chiselled and stitched by hand — 2.8mm thick, 20mm at the lug tapering to 16mm at the buckle, on quick-release spring bars. This one is Black, full-stitched in black thread.
A strap that outlives the watch.
Cordovan patinas rather than cracks — treated well, it still looks the part long after the trend that sold it to you.
Double-sided cordovan.
Shell cordovan for the lining as well as the face, where most makers use a cheaper backing — so there's no rough flesh side against your wrist, and nothing to crack.
Shinki Hikaku horsehide.
From the Japanese tannery renowned for the glassiest, most uniform shell cordovan made.
Hand-stitched, full.
Every stitch placed by hand in black thread, running the full length of the strap.
Quick-release, 20/16.
Quick-release spring bars swap it in seconds, no tools. 2.8mm thick, 20mm at the lug tapering to a 16mm buckle.
Heads up — how a strap fits
Any 20mm-lug watch. These are 20/16 straps — 20mm where they meet the case, tapering to 16mm at the buckle, on standard quick-release spring bars. They fit our 20mm-lug cases and any other watch with 20mm lugs. (Two of our own cases are exceptions: the Bauhaus 33 runs 18mm lugs, and the Seiko-Dweller’s bracelet is integrated.)
Sold by wrist size. Pick by your measured wrist — full size chart in the Sizing & Fit tab. Between sizes? Size up.
Heads up — about the colour
Every strap is photographed under studio lighting with the colour left unedited. Screens still render tone their own way, so it may look slightly different in person. Black is the one shade that stays consistent from batch to batch.
Leather & Make
Dimensions
Buckle & Fittings
Pick your size
| Size | Wrist | Long / Short end |
|---|---|---|
| Small | 14.5 – 17.0cm | 105 / 65mm |
| Medium | 16.5 – 19.0cm | 115 / 70mm |
| Large | 18.5 – 21.0cm | 125 / 75mm |
Between sizes? Size up — e.g. a 16.8cm wrist takes Medium.
Fitting it
Quick-release spring bars are fitted — slide the tab, drop it between the lugs, release. No tools, no scratched lugs. Fits any 20mm-lug watch on standard spring bars.
Building a Seiko mod? See our complete build guide .
All photos of watches with modification parts are for illustration purposes only and are not included with the strap purchase.
Everything worth knowing before you build.
![Shell Cordovan Leather Strap 20/16mm [Black, Full Stitch] - Small (14.5 - 17.0cm) - - - Lucius Atelier - Swiss Quality Seiko Watch Mod Parts](http://luciusatelier.com/cdn/shop/files/Shell-Cordovan-Leather-Strap-2016mm-Black-Full-Stitch-Small-14_5-17_0cm-Lucius-Atelier-Swiss-Quality-Seiko-Watch-Mod-Parts_1600x.jpg?v=1707333508)
![Shell Cordovan Leather Strap 20/16mm [Black, Full Stitch] - Small (14.5 - 17.0cm) - - - Lucius Atelier - Swiss Quality Seiko Watch Mod Parts](http://luciusatelier.com/cdn/shop/files/Shell-Cordovan-Leather-Strap-2016mm-Black-Full-Stitch-Small-14_5-17_0cm-Lucius-Atelier-Swiss-Quality-Seiko-Watch-Mod-Parts-2_1600x.jpg?v=1707333513)
![Shell Cordovan Leather Strap 20/16mm [Black, Full Stitch] - Small (14.5 - 17.0cm) - - - Lucius Atelier - Swiss Quality Seiko Watch Mod Parts](http://luciusatelier.com/cdn/shop/files/Shell-Cordovan-Leather-Strap-2016mm-Black-Full-Stitch-Small-14_5-17_0cm-Lucius-Atelier-Swiss-Quality-Seiko-Watch-Mod-Parts-3_1600x.jpg?v=1707333518)
![Shell Cordovan Leather Strap 20/16mm [Black, Full Stitch] - Small (14.5 - 17.0cm) - - - Lucius Atelier - Swiss Quality Seiko Watch Mod Parts](http://luciusatelier.com/cdn/shop/files/Shell-Cordovan-Leather-Strap-2016mm-Black-Full-Stitch-Small-14_5-17_0cm-Lucius-Atelier-Swiss-Quality-Seiko-Watch-Mod-Parts-4_1600x.jpg?v=1707333523)