Cateye Volt 800 - Great light, great mount.

Cateye uses the same mount for their 300 lumen light, all the way up to their 1600 lumen light.

I use the Cateye Volt 1600 and the light is very stable and doesn't move at all, unless my big belly crashes into it.

The Cateye Volt 50 Rear Light also works with this mount too.