Draper - 1/2" Sq. Dr. Wobble Extension Bar Set (Micro Satin Chrome) (4 Piece) Expert Quality, with wobble end, manufactured from chrome vanadium steel hardened and tempered with a micro satin finish. Each ext. bar has a knurled ring for extra grip. Machined wobble end allows sockets to be driven at up to 15° to the vertical. Attached with a spring - loaded ball bearing for secure socket holding. Display Packed.