the cateye of-200 is a supremely strong, cold forged aluminium bracket designed to support cateye computer head units, cateye head lights which use the flex tight fixing system, & action sports cameras using the go pro attachment system.angle adjustment for the light is very easy, thanks to the inclusion of a cateye compatible go pro bracket adapter. The go pro adapter can also be removed for use on helmets supporting the same attachment system.compatible lights: volt 300, 400, 800, 1200, 1600, 1700, 6000.suitable for fixing to the left or right hand side of the handlebar stem, with stainless steel fixings, the cateye of-200 weighs just 71g & has a durable shot-blasted matt black finish with gloss black cateye branding.max handlebar diameter: 31.8mm (without spacer ); 25-26mm with spacer, included.