The Easy Racer Chain Roller Guide provides a precise and smoothe running path for your motorized bike chain. Forget the plastic bushings and bad bearings of other rollers and pullies! This chain guide has an ABEC-5 skate bearing to keep up with the fast moving chain from your engine. Most other pulley bearings wear easily from the speed your bike gets up to, but the ABEC-5 bearing will be able to run smoothe going up to 35mph. No more early wear and all the precision you can ask for, the Easy Racer Chain Roller Guide is perfect for your next motorized build!