This is the Adjustment Tech ride height adjuster for the YZF-R1. By turning the 15/16" nut, you can raise or lower the rear of the bike by 2+" in less than a minute. Installation is simple, just support the rear of the bike and remove 2 screws. Lowering the front can be accomplished by loosening the allen head screws that clamp the forks. Adjustment Tech is in Canada and can be contacted at 705-799-5139, ask for Andrew.