Features: _x000D_ Drill bit is made from carbon steel and countersink is made from good quality 45# steel which ensures a long service life. _x000D_ Combined drill bit and countersink bit is great for drilling, chamfering, deburring and countersinking. _x000D_ There are 10 sizes of 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 7mm, 8mm, 10mm and you can choose the one you need._x000D_ _x000D_ Five flutes design provides small chip loads and quicker removal, it can discharge wood sawdust more rapidly and smoothly. _x000D_ Suitable for drilling holes on board of low hardness such as wood, plastic and other soft material._x000D_ _x000D_ _x000D_ _x000D_ Specifications: _x000D_ Material: Carbon steel(drill bit), 45# steel(countersink) _x000D_ Countersink Flute: 5_x000D_ _x000D_ Drill Bit Diameter: 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 7mm, 8mm, 10mm, 3-10mm(3/4/5/6/7/8/10mm), 3-6mm(3/4/5/6mm)(Optional) _x000D_ Countersink Diameter: 15.8mm _x000D_ Hex Key Size: 55 x 20mm _x000D_ Quantity: Your choice _x000D_ _x000D_ _x000D_ Package Includes: _x000D_ 1pc(or 1 set) x Countersink Drill Bit _x000D_ 1 x Hex Key _x000D_ _x000D_ _x000D_ Note: There are only 7pcs in 3-10set, and only 4pcs in 3-6set.