My great grandfather was a Navy lieutenant stationed on Ford Island when the attack on Pearl Harbor happened. He found this object ( https://m.imgur.com/nH9XE7t ) on the island in the days after the attack, however we haven't ever been able to identify it. I think it might possibly be a timer dial from the tip of a bomb dropped by a Japanese plane. The numbers inscribed on the outer rim of the dial go from 0-50. If anyone out there has any information I'd be very appreciative for your help in identifying this!