Lemania Stop Watch ?

Hi I bought box of watches and have what I think could be an early wrist worn stop watch possibly military.Cant get the back open tried everything and don’t want to damage.Have seen similar but not sure if this is the right make to research further.

 

Think this is a single button fly back stopwatch possibly military , aircrew or pilot will post the movement and maker on when I know better , “Still Searching”(Bob Seeger).

 

where exactly is the Lemania name coming in ?
is it a 60 seconds/ 30 minutes stop watch ?
what sports would need such a time span ? 5 miles run ?

 

Finally got the case opened just says Swiss made and 288 on the movement and a serial number on the back of the chrome case.

 

288 could be a calibre number of the work. you'd eventually find some hints with the 288 and the serial number together. good luck.

 

Thank you for looking .