ITEM NAME:5PCS Titanium Spiral Grooved Step Drill Bit Set with Automatic Center Punch N9A7 5PCS Titanium Spiral Grooved Step Drill Bit Set with Automatic Center Punch N9A7 1. Drills holes of various sizes without changing bits. 2.Smoother and rounder holes. 3.Minimal shocks and almost impossible to snap compared to conventional bits. 4.Prevents metal scurf from flying around for improved safety. 5.Suitable for steel sheets, aluminum sheets, wood board, plastic board etc. Note: 1. Not compatible with hammer drill. 2. Please do not set drilling speed too high to avoid damages to cutting edge. 3. It is recommended to oil the bit before every use. 4. Please drill a smaller hole to make drilling smoother. 5. The metal sheet on which you want to drill should not exceed 0.38 in. in thickness. Material:High speed steel colour:Gold Package Contents: 5 * step drill 1 * Step Drill Bit