8740 B HF. 3/8" drive for Hex (Allen head) socket bolts/ screws. These socket bits come with holding function and Hex-Plus bits, offering a larger tool to bolt contact to prevent bolt damage. Compatible with all hex (Allen head) bolts. Chrome vanadium with a brushed chrome plated finish and color coded for finding the right size quickly. Knurled at the base for easier manual turning. With ball intercept ring. Note: Not compatible with impact wrenches. Size: 5/16". Overall length: 100mm.