The sockets include "DirectTorque" technology to help prevent rounding of fasteners and to provide better grip. Set includes 3/8 in drive pear head ratchet, 3/8 in drive extensions: 3 in and 6 in, 3/8 in drive spark plug socket 5/8 in, 3/8 in drive 6-point sockets: Metric 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm and 18 mm.