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: 0.9mm / 0.035-inch Drill Bit Length: 11mm / 0.43-inch Shank Diameter: 0.6mm / 0.024-inch Total Length: 25mm / 1-inch Package Content:5 x Diamond Twist Drill Bits