The Mission Impulse PC pedals are molded from a plastic composite with 10 traction pins per side and a knurled concave body for extra grip, chromoly spindle and unsealed bearings. Keyed for 6mm Allen wrench. 9/16" Features Weight: 402g 9/16" chromoly spindle Works with 15mm box wrench or 6mm Allen key Micro-knurling for extra traction 10 moulded pins per side Comfortable concaved body Nylon with glass material