Features and Benefits: This adapter allows the use of Grey Pneumatic impact sockets on a standard drill chuck and are especially useful with our magnetic sockets; Made from the same high quality steel as our impact sockets for extra durability and long life; Feature a spring loaded friction ball retainer; Heat treated for strength and durability; Black oxide coated for resistance against rust and corrosion; 1/4 in.; Hex x 3/8 in.; Square Adapter w/ball retainer