The Shadow Conspiracy Disaster Sprocket Guard is designed to fit most 5 and 6mm thick sprockets by sliding over the crank spindle and attaching using the existing sprocket bolt for a universal fit. CNC machined from aluminum, the Disaster guard will help protect the sprocket teeth and chain from damage caused by grinds and sprocket stalls. 15/16" (24mm) bore with a 19 and 22mm adapter included.