Descriptions: Fits for drills, flex shafts, bench drill and hanging mill. Suitable for drilling holes on glass, shells, rocks, marble, stones, etc. Note: Add the coolant can increase work efficiency and extend service life. Specifications: Color: Silver Tone Material: Diamond, High Speed Steel Drill Bit Diameter: 1.7mm / 0.067-inch Drill Bit Length: 14mm / 0.55-inch Shank Diameter: 1.2mm / 0.047-inch Total Length: 38mm / 1.5-inch Package Content:5 x Diamond Twist Drill Bits