1/4" square drive imperial hex sockets manufactured from chrome vanadium steel, hardened, tempered chrome plated & polished, chamfered ends for positive nut location & special radius design to give added torque & life expectancy. Sockets have a knurled band for extra hand grip & a hole for positive ball retention. Manufactured in accordance with DIN3124/ISO2725 & DIN 3120/ISO 1174. Set contents 3/16, 7/32, 1/4, 9/32, 5/16, 11/32, 3/8, 7/16 & 1/2 AF.