Armstrong Socket, Deep Length, Series, Measurement System, Square Drive, Drive Size, in 3/8, Socket Size, in 5/16, 2-1/2 Overall Length, Opening Depth in, in 0.44, 0.648 Drive End Width, Socket End Width in, in 0.49, Ball Locking, Number of Points, Bolt Clearance Depth, in 0.31, High Alloy Steel, Finish