High quality The extension kits are made from heat treated chrome vanadium steel with a black Oxide coating, and the adapters and reducers are made from high strength, Premium chrome molybdenum chrome steel with corrosion resistant manganese phosphate coating, so you know this set is built to last Features These extensions are made of 1/4 inch hex shanks and are heat treated. Chrome vanadium steel with a black oxide coating, so you can rely on them to work when you need them and to withstand high torque situations. 8pcs Drill Socket Adapter Size: Suitable for all sockets, for direct drive via chuck or with 1/4" hex socket Shank 1/4" standard hex, all sockets 1/4 inch Hex Shank to: 1/4 inch square drive x 4pcs 3/8 inch square drive x 2pcs 1/ 2 sq inch x 2pcs 4 Piece Impact Adapter Set Size: 3/8"(F) to 1/4"(M) Reducer 1/2" (F) to 3/8" (M) Reducer 1/4" (F) to 3/8" (M) Drive Adapter 3/8" Drive Adapter in. (F) to 1/2 in. drive (M) Package included: 8 piece extension set - 1/4" 3/8" 1/2" 4