IRWIN 1877499 Impact Performance Series Deep Well Square Drive Socket Reducer, 3/8-Inch Square to 1/4-Inch Square Built for maximum durability and long life with impact drivers Made from heavy-duty chrome molybdenum steel for maximum durability and long life with impact drivers Black oxide finish resists corrosion and increases life Connects 3/8" square drive drills or accessories to 1/4" square drive sockets or accessories Manufactured with heavy-duty, cold-forged, high-grade steel to withstand high torque output