A handlebar mount for the hexbright flashlight. The hexbright just snaps in and is held very securely. I've been riding with it for a week in NYC and haven't had any problems with it coming loose.
Two zipties and a piece of old inner tube make the mounting easy.
This thing was made with Tinkercad. Edit it online https://tinkercad.com/things/bv38Euyc4ur