This is a 1960s-70s Hamilton military watch in solid steeel case. The cas of the watch is being cast from aone block of steel which made it very tough for use in extreme condition.
I was trying to collect a series of military watches as these watches were issued to servicemen from the various armed forces and owing to the nature of the job, it is extremely difficult to find them in such nice condition.
I found this watch in the 1980s when I was still in the University. I bought this watch from an Englishmen staying in Singapore.