The hardness of teeth is HRC4-48. The working depth is up to 25mm. Wood Hole Saw/Wood Drill is made of high-quality steel and can be used for drill holes on wood and PVC pipes. It is mainly used for household down light spotlight, it can not be used for metal plate and stone. After use, a small amount of anti-rust oil is supposed to added on the surface of the opener to avoid natural oxidation, and which can also improve the service life.

Specification: ordinary black/yellow/upgraded red/high grade blue with different sets available:
5PC（20*15*4cm） 0.8kg； 8PC（20*11*4cm） 0.4kg； 13PC（20*15.5*4cm） 1kg

The external cooling liquid is better to added to when drilling the metal material. In case of any stop caused by the trash materials during operation, it is necessary to stop the operation first and then continue to work after discharging the waste.
Do not use too much force when disassembling and assembling screws. When drilling holes on the material with a thickness of more than 10 mm, it is necessary to remove the spring on the positioning drill.
Bi-Metal Hole Openers/Hole Saws/Bi-Metal Drills are widely used in all kinds of bench drill, drilling machine and electric hand drill.

Note: before use, make sure that all the screws of the product have been fixed. First to test with the electric hand drill to see whether the blade is fixed properly, and then open the hole to avoid improper operation.