I no nothing about this watch, please help.
It’s working very well

 

Likely a caliber 12.68Z from the mid-1950's. More information can be obtained by opening the watch and contacting Longines with the serial number on the movement.

 

An interesting dial might be hidding beneath that battered crystal. Pic of movement and inner caseback needed for knowing more.

 

Maybe it`s issued Or maybe just wear from a perlon strap, popular in Scandinavia....