The park tool fr 6 freewheel remover is made of heat treated alloy tool steel one inch base fits wrench or bench vise thin wall construction allows use without removal of cones and locknuts park tool fr 6 freewheel remover features removes four notch bmx single speed freewheel from hubs with 137 x 24 tpi threads the fr 6 has four notches approximately 32mm across measured inside to inside and 40mm outside to outside fits over axles up to 16mm thread diameter always hold the r