A great Omega stopwatch from the 1970s in excellent condition. Clearly had little use.

Mark on the case back at 45. See the picture

1/5 second index with 30 minute accumulator. Full working order.
 
Marked Omega on the dial. Whilst it's also stamped Omega on the movement it was in fact made for them by Lemainia. The Lemania maltese Cross appears under the balance wheel.