This
Helmet Strap from
GoPro is designed specifically for use with vented helmets. The strap allows your HERO camera and its quick release housing to attach to the base plate, mounted on your helmet. This is the same Helmet Strap that comes with the Helmet HERO camera and can be used as a replacement or extra strap for those with more than one helmet mount.
+ Allows the camera and the quick release housing to fit onto the base plate mounted to the top of your helmet
+ Designed specifically for vented helmets