the back just has waterproof, shockproof...open thru crystal
'BENRUS' stamped at the bottom
maybe a '60's watch?
also the hour is set by turning the crown anti-clockwise
if it needs to be set a few days forward then
just wind it to 12 then back to 9 then to 12 and the date changes
also i hadn't wound it for a while and the date was ahead and i could not get the date to go backwards.
just wanted to get general info
with the speidel band it looks real nice