3/4" drive, 12-point short socket 2-1/4" They feature a chrome-nickel finish to prevent corrosion. Drive end outside diameter: 1-7/8”. The sockets drive attachment system consists of an internal groove on all four walls, allowing it to easily attach to accessories and ratchets. The 12-point design has the advantage of distributing better force around a larger area on the nut faces, more toward the center, not on the edges.