meri high quality, full of particles: high quality widened and sharpened meri teeth are more durable than ordinary glass bell saws. Cutting design, more efficient perage : The special opening design has a smooth nickel surface and significantly reduces the sistance, which improves the efficiency of the notch and the opening of the holes. Optimize the design of the chip slot and the chip slot is fluid: the slag after opening is cleaned of the chip slot and, At the same time, it plays a role in heat dissipation during the opening process. Suitable for electric hand drills and bench drills, universal rod type: the universal round rod is suitable for electric hand drills and bench drills, with complete specifications to meet various drilling needs. Name: glass hole opener Spcifications: 3 mm, set of 8 Matriau: high quality meri Uses: can be used for glass, tiles, marble, cramic, etc. Fragile and hard matrix for perage, Suitable for hand drill/apbot drill, please do not drill tempered Water should be added during the hole opening process. Proper cooling can extend the life of the drill. Do not drill without adding water, otherwise it will easily damage the drill. Since the glass bell saw does not have a central drill, it must be slowly actuated a bevel of 45 degrees. After contacting the glass, after opening the alvolary crescent trace, he can play a positioning role, then straighten the electric drill to open the hole vertically