Teng Tools Impact Sockets are manufactured from top grade chrome molybdenum alloy steel in accordance with GGG-W-660A to give a top quality, professional range of impact sockets. Teng Tools impact sockets have been especially developed for air tool usage. In no circumstances should regular chrome vanadium sockets be used with power tools. 10 piece 1/2 in square drive deep metric impact socket set, covering 10 to 24mm. Contents : 10, 11, 12, 13, 14, 17, 19, 21, 22, and 24mm.