RE: [Demo notebook] Reference notebook: corrections and recurring beginner questions · RWI-00544

Case 4 — Strap dimensions: lug width, taper, thickness and spring bar diameter explained

A notation like 20/16 means 20mm at the lugs, tapering to 16mm at the buckle. Taper affects look and comfort more than fit. A strong taper suits smaller and dressier cases, a straight strap suits sport watches. Your buckle or clasp also has to match the narrow end, so check that if you want to reuse an existing buckle.