Step-Drill-Set-4-32mm-3-Piece-Blue Spot-Tools-20504-p-The-Blue Spot-Step-Drill-is-manufactured-from-high-steel-for-increased-durability-&-cutting-power-Titanium-coated-to-reduce-friction-&-heat-Specially-designed-for-precision-drilling-of-holes-in-aluminium-brass-copper-plastic-steel-&-wood-2mm-step-increments-p-p-The-set-is-supplied-in-a-robust-metal-case-&-contains-the-following-p-p-1-x-5-Step-Drill-4-12mm-br-1-x-9-Step-Drill-4-22mm-br-1-x-10-Step-Drill-4-32m