Drillpro 3 Pack Power Driver Extension Socket Adapter Bit Set, 1/4'', 3/8'', and 1/2'' Drive+ Impact Adapter and Reducer Set, 4-Piece A total of 7 pieces: Adapter Hex to 1/4 "/ 1/2" / 3/8 "square + adapter set (CONNECTOR), 4 pcs 3 Piece Socket Adapter For mounting nuts / plug nuts 1/4 3/8 1/2, connection of adapters: 1/4 inch hex Adapters Set , 4 pcs: 1/4 inch to 3/8 inch; 3/8 inch to 1/4 inch; 3/8 inch to 1/2 inch; 1/2 inch to 3/8 inch For cordless screwdrivers and drills, for all drills and screw drivers etc. Application: industry, crafts and handyman