... Brazed Protection 2.Speed:3000-10000rpm 4.40-60s/hole for 3cm granite 5.Lifetime:80-120 holes Diamond Hole ... 1, Fast and smooth drilling at high speed.2, Suitable for dry drilling stone.3, Welded by Laser and vacuum brazed and ... reducing heating4, Never tip off and amazing long life. Application:For drilling granite, marble, oncrete, ceramics, etc. Diameter ConnectionLengthApplication 20mm ...