Wheels Manufacturing Thin Flange Bottom Bracket Socket - Praxis, 50mm, 12-notchThin Flange Bottom Bracket Socket Designed to create a tight grip on thin flange bottom bracket to avoid slipping while torquing cups into bike frames. Compatible with all Wheels Manufacturing (Praxis T47) bottom brackets that have the following spline patterns: 50mm, 12 notch 1 2 UNC threaded Press Rod Machined 3 8" drive, which can be used to allow 3 8" drive torque wrenches to be attached Locks onto 1 2 inch UNC press rod Machined 6061 aluminum