Bottom Bracket SocketDouble sided socket tool for installing and removing both 48. 5mm and 44mm 16 notch bottom bracket cups. Compatible with all Wheels Manufacturing bottom brackets. Socket is machined for 1 2" drive, but a 3 8" to 1 2" adapter is included so you can use it with 3 8" drive torque wrenches. 48. 5mm, 16 notch pattern matches up with Wheels Mfg bottom brackets, along with some FSA MegaEVO bottom brackets. The 44mm, 16 notch side matches up with Wheels