XCAN 3pcs  3-12mm 4-12mm 4-20mm HSS Straight Groove Titanium Coated Wood Metal Hole Cutter Core Drill Bit Set    Suitable for: Products for automotive processing, aerospace, sheet metal processing, Installation and maintenance of electrical and other industries, High-altitude operations with hand drills and other tools.   Feature : 1. The unique step structure, a variety of standard size drill carve aperture, a box arrived on a ladder drill bit. 2. Without the use of center punch, easy to break, a step drill specifications apply. 3. Deburring, chamfering, expanding the oval hole 4. Small sway, without leading to use a center punch can carve out a nice aperture. 5. Surface treatment: Titanium  Sizes: 5 step drill bit: 4-12mm (4mm, 6mm, 8mm, 10mm, 12mm)  9 step drill bit: 4-20mm (4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm)  10 step drill bit: 3-12mm (3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm)  Package Included: 1 x 3 PC HSS step drill