Size:4Pcs Diamond Drill BitsDiamond Drill Bits Diamond Point Ideal For Porcelain Tiles, Granite, Marble, Stone, Masonry, Brick Etc.Feature: Material: Stainless Steel And Coated Ment Diamond; Stem: 6 Mm Diamond Coating Up To 10Mm Size: 6Mm, 8Mm, 10Mm, 12Mmpackage: 4Pcs Brazed Diamond Drill Bits Vacuum BrazedWarm Tips:Using Tips For Vacuum Brazed Diamond Core Bits1.Do Not Use These Drill Bits With Hammer Mode 2.Do Not Install These Bits Only On A Drill Press. Cord, Not On A Cordless Drill (Not Enough Power) 3.Only For Tile Drilling, Not Recommended. For The Material Behind The Tile 4.For Horizontal Drilling, Just Give Light Pressure, For Vertical Drilling, The Weight Of The Machine Will Give Enough Pressure. Drill According To The Following Instructions: 1) Place The Drill At The An Angle Of 45 Degrees 2) Drill Until What The Hole Starts At; Form 3) Bring The Drill To A Vertical Position 4) Continue To Drill; To Drill And To Swing The Machine Along A Circle