Bike Chainring Sprockets Cranksets Guard Protector 48t 4 Bolts 120mm Bk34 Size:48T, 4 bolts, 120mm Function: Prevents chain from jumping to the outside Color: Showed in the picture Material: Engineering Plastics How many teeth of Cranksets? What size you can measure the diameter of the adjacent holes? Then you can choose which one you can buy .