Wheels Manufacturing Thin Flange Socket - PraxisPraxis Thin Flange T47 Bottom Bracket Socket Designed to create a tight grip on thin flange bottom bracket to avoid slipping while torquing cups into bike frames. This single sided socket is used for installing and removing 50mm, 12 notch bottom bracket cups. The socket has a machined 3 8'' drive, which can be used to allow 3 8'' drive torque wrenches to be attached and locks onto 1 2 inch UNC press rod for secure and easy installation of thin flanged