Chromyl steel and custom heat treatment for maximum durability in high torque applications. Radius corners drive on flats to reduce stripping and breakage. Thin wall construction for impact strength in tight clearance applications. Set includes 1 each: 1/4" hex to 1/2" square adapter, 3/8", 7/16", 1/2", 9/16", 5/8", 11/16", 3/4", 7/8" Shockwave impact sockets. No. 49-66-4484: Drive Size: 1/2 In., Pieces In Set: 9 pcs, Finish: Black Oxide, Pkg Qty: 1, Package Type: Clamshell