So these are the spares we had made, that were supposed to be the “dive bezel insert”. It has individual gradations from 12-3 to be able to time something to the minute, for 15 minutes. Beyond 15 minutes, you’d still be able to use the rest of the hours on the insert as 5 minute increments for timing.
Grab a spare bezel insert to switch out, or to age for that vintage look!
31.25 ID/38.5 OD