Leadrise&reg; 3pc Swivel Universal Joint Air Impact Socket Set Sizes =1/2" -3/8" -1/4 Inch Drive Made from high quality chrome vanadium steel, precisely heat treated and protected by a durable, corrosion-resistant chrome plated finish. Works around obstructions to access hard-to-reach fasteners to give you a better angle. Locks onto socket and drive tang, detent notches in drive ends lock onto ratchets and extensions. Spring-loaded detent balls securely latch onto sockets, preventing them from being dropped. Package included 3-Piece universal joints: 1/4, 3/8, 1/2 inch.