This is a sturdy, precisely machined mount for attaching your dynamo headlight to your fork crown hole. Use the included spacer for additional standoff to help your light clear the straddle cable of your cantilever or v-brakes.
This mount is not compatible with brakes whose straddle cable hanger sits below or in front of the crown hole. Your straddle hanger must sit above your crown hole. Disc brakes? No problems!