[High Quality] Made of high quality diamond material, with nickel plated coating, rust and corrosion resistance, high hardness, thick diamond coating tip, good wear resistance and long service life [Precise Drilling] The thickened diamond tip with excellent cutting force, allowing high precision and smooth cutting without broken edges, perfect for drilling clean and accurate holes [Easy to Use] Just start drilling at a 45 degree angle and align the hole shape at a 90 degree angle to complete drilling, center guide holes and side holes help to easily remove chips [Size] Aperture: 8 mm; Drilling Depth: Max 30 mm; Total Length: Approx. 50 mm; Bit Holder Diameter: Approx. 5.5 mm; Number of revolutions: 800/min maximum, come with 60 pieces drill bits to meet the wide range of drilling needs [Applicable] It is recommended to reduce drilling speeds, low drilling pressure and it is necessary to cool the drill when using it, in order to greatly extend the life of the drill bit. Suitable for