4pc SAE 15° Offset Double Ring Geardrive Spanner Set • 5/16x3/8 7/16x1/2 9/16x5/8 & 11/16x3/4" Geardrive technology • Heat-treated chrome vanadium steel for strength exceeding international standards • Small head profile designed for working in confined spaces • 72 Teeth needs as little as 5º to move fastener