HSS-Step-Drill-4-22mm-Blue Spot-Tools-32050-p-The-Blue Spot-HSS-Step-Drill-is-manufactured-from-high-speed-steel-for-increased-durability-&-cutting-power-Titanium-coated-to-reduce-friction-&-heat-With-10-Steps-4-22mm-in-2mm-increments-Specially-designed-for-precision-drilling-of-holes-in-aluminium-brass-copper-plastic-steel-&-wood-p-Blue Spot-Tools-32050-HSS-Step-Drill-4-22mm