Motion Pro Revolver Variable-Rate Throttle Kit 01-2647 Innovative reel changing system allows you to tailor your throttle rate to riding conditions or rider preference Kit includes four reel sizes 35mm, 40mm, 45mm and 50mm Use the smallest reel for slow throttle rate and largest reel for fastest throttle rate Unique reel design allows fast reel changes without having to readjust cables Cable boot keeps dirt and dust out for reliable, smooth operation