Hamilton Model 21 WW2 Ship Chronometer Trip Spring chronometer Stainless steel snap-on back is

Stainless steel snap-on back is inscribed with the following:

We also have the female part that snaps onto it

This watch has been oiled

Note: the movement ring is sold separately

Hamilton Model 21 WW2 Ship Chronometer Trip Spring chronometer Stainless steel snap-on back isThis is a "trip spring" for the spring detent (shown in picture to its right) for a Hamilton model 21 movement (last picture). Over time the end of the trip spring wears and it must be replaced. Note that we service these chronometers and have more parts. Email us with your needs. We also have the repair manual and can download you a copy. Photo of model 21 movement for display purposes only.