Features and Benefits: Radius V-Grove design createsan anti-slip and preventsrounding of the fastener; Radius Corners on the box endto grip the flat sides of thefastener and prevent round-off.; Upgraded steel from High Carbon to Chrome Vanadium; 30% more strength and durability; Chrome plating to prevent rust, corrosion and deformation; Available individually or as part of the 9917MA 12 Pc Metric Full Polish V-Groove Combination Wrench Set OR as part of the 9917MPRA 25 Pc Metric Full Polish V-Groove Combination Wrench Set