Steel manual wind DOXA from the 1950s...
'Rare' German made steel 'Sliplock' bracelet...
Imho the term 'rare' is much like 'near mint' and 'like new' when applied to watches.
I call it 'rare' only because it is the only example I have seen in 40+ years. It is similar to a Bonklip.
You let enough of the clasp cap end of the bracelet out (at the top of the pic) to go over the wrist, then pull it as tight as needed and snap the two pieces of the clasp back together.
I made up the term 'Sliplock' years ago.
Modern Bonklip type bracelet...
Bonklip Bracelet - 304L Stainless Steel Watch Band - Adjustable Size (josephbonnie.com)