SKS Chainbow Bosch chain guard The adjustable profile of this chain SKS Chainbowguard covers the entire length of the chain. The pants stay clean and you are protected against injuries. The aluminium rail covers the top and fixes the screen to the back. Since the holder is mounted behind the crankset bearing cup, a crank buyer is required for assembly. Specifications: Color: black Material: plastic, aluminum Suitable for: 38T Crank hole diameter: 158 mm Length: 37 cm Height: 18 cm Weight: 235 grams Type: Bosch Comes with bracket bracket.