The Knog PWR Helmet Mount is perfect or holding charger and modular lights on top of helmet (Excludes PWR Mountain). Tri-prong system works with GoPro, so can be used to mount lights under Garmin and other mounts. Knog PWR Helmet Mount Features Compatibility - Works with PWR Charge and Modular lights (not PWR Mountain). Mounting System - Designed to fit most vented helmets, common for road and trail cycling. T Slot (For modular) - Allows for quick release of the light when parking your bike. Mounting - Fits vented bike helmets & is GoPro compatible. Weight - 20g.