14578 - Stepped Drill Bit - 4-12mm

Drill multiple size holes with the one bit! You can drill through plastics and un-hardened metals (such as aluminium or copper sheeting etc). Doesn't need a pilot hole.  A great benefit of using the step drills is all you need to do to de-burr the hole is drill a little bit further so that the next size up touches the hole! Made from high speed stainless steel (HSS), they will last for a very long time. 4-12mm in 2mm steps.

(AAA Battery is for size comparison only)