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 1609/2hobby wrench also fits on the external centerlock disc nut.Features:Material: premium flex plus carbon steelSurface finish: chrome plated according to iso 1456:2009Tool also fits the disc brake rotor nuts with 16 external notches.