SRAM 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 52mm, 16-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 bottom brackets. Machined 6061 Aluminum Anodized Red