Kamasu GMT

Ref. RA-BC0001B30B

Case diameter: 42.8 mm; Manufacturer spec
Lug-to-lug: 49.5 mm; Manufacturer spec
Thickness: 13.4 mm; Manufacturer spec
Lug width: 22 mm; Manufacturer spec

Retail price $495 (US, Oct 2026)

Your wristIdeal fit

Wrist flat: 55.1 mmLug-to-lug: 49.5 mm

How the Kamasu GMT wears

Its lugs add 6.7 mm to the 42.8 mm case, close to the 7 mm typical across the almanac, so its diameter is a fair guide to how it wears.

On our fit model it sits best on wrists from 7" to 8.25" (17.8–21.0 cm); below 7" the lugs start to reach the edge of the wrist.

At 13.4 mm thick it is thicker than 70% of the 142 other dive watches we've measured, so expect it to sit tall on the wrist.

Its 22 mm lug width is one of the most common strap sizes; 56 other watches here share it, so aftermarket straps are easy to find.

Will the Kamasu GMT fit your wrist?

With a 49.5 mm lug-to-lug, here is how it wears across common wrist sizes. We estimate the flat top of each wrist from its circumference; measure yours for a closer answer in the fit finder.

Wrist	Flat width (est.)	Fit
6"	47.2 mm	Lugs overhang
6.5"	51.2 mm	Snug, lugs near the edge
7"	55.1 mm	Ideal fit
7.5"	59.1 mm	Ideal fit
8"	63 mm	Ideal fit

Specifications

Reference: RA-BC0001B30B
Collection: Kamasu
Status: In production
Introduced: 2026
Case material: stainless steel
Crystal: sapphire
Water resistance: 200 m
Bezel: 120-click unidirectional
Dial: black
Strap / bracelet: stainless steel bracelet, solid end links, foldover clasp with safety
Style: Dive, GMT

Movement

Caliber: Orient F6P22
Type: automatic
Power reserve: 40 hours

Takes 22 mm straps. See other 22 mm watches and straps.

Watches that wear the same size

Other watches within 1.5 mm of its lug-to-lug.

Same 22 mm lug width

All 22 mm watches

These take the same straps as the Kamasu GMT.

Sources

orientwatchusa.com/products/ra-bc0001b30b