Individually tested to exceed standards. Two layers of insulation for protection against electric shock. Cushion-grip handles for greater torque and comfort. Patented Tip-Ident® quickly identifies nut driver and size. Full hollow shafts facilitate work on long bolt applications. Custom US-made tool steel. Set includes 3/16-" 1/4" - 5/16" - 11/32" - 3/8" - 7/16" - 1/2" - 9/16" - 5/8". Custom Cordura® case with document pocket.