These "Frictionless" Chain Guide Blocks are CAD designed and CNC
machined using UHMW-PE composite material. Thanks to its extremely
low coefficient of friction (0.14), outstanding abrasion resistance,
superior impact resistance, and self-lubricating properties, UHMW-PE is
ideal for getting you through the gnarly stuff. Outlasting OEM chain
guides, while offering a practically frictionless guide and unbelievable
protection for your chain and sprocket. The BRP Guide Block is able to absorb a
hit without bending like the stock aluminum chain guard. Two-piece design easily
replaces the OEM chain guide.