Shop quality fiber reinforced nylon socket with center post for damage-free installation and removal of 16-notch BB cups Center post helps to fix and stabilize the tool on to the BB cup 1/2` drive is compatible with ratchet and torque wrenches External BB Socket Black/Silver 30mm 16-Notch x 48.5mm 1/2`UPC/EAN/GTIN: 888571070055