Onyx Racing Products Vesper MTB Boost RearOnyx hubs transfer the precise amount of torque you want to the ground when you need it. Nasty climbs on boulders and rock require just the right amount of instantaneous power but only at your command. There is no substitute for absolute control of your machine Listen carefully. Only the sound of the wind in your face separates you from the mountain. Enjoy the music of nature unfettered by the rancorous clicking of pawls. Onyxs patented sprag clutch