Starts bit drilling on center, eliminates the need for a center punch. 12 inch (300mm) long, perfect for thick pieces of wood Made of high carbon steel with heat treatment, HRC48~50 Sizes include: diameter 4mm, 5mm, 6mm, 7mm, 8mm,10mm, 12mm Our wood drill bits are perfect for extra deep holes in materials such as softwood, hardwood, plywood, chipboard, hardboard and many plastics. size: 300mm Material: high speed steel colour: silver + black Package Contents: 7 x Drill Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.