The open bottom bracket wrench is used to remove and install shimano hollowtech ii campagnolo ultra torque and power torque race face fsa sram truvativ chris king bottom brackets as well as many and others the 16092 wrench also fits on the external centerlock disc nut material special tool steel hardened and tempered surface finish chrome plated according to en12540 tool also fits the disc brake rotor nuts with 16 external notches