Diamond Core Drill Bit,Brschnitt 1 Inch Laser Welded Diamond Hole Saw With, 25Mm Size --1pc 1 inch core drill bit (25mm),diamond height 10mm, total length 100mm,diamond grit #25/35,working length 80mm,5/8-11 thread of the granite drill bit Wide Application --Diamond drill bit are worked great for dry drilling holes through Granite Marble Hard Stone Reinforced Concrete Brick Block Counter Top,Using water could prolong the lifetime Super Quality Raw Material --Using laser welded technology,improve the performance of segments,avoid segments off during drilling process.The vacuum brazing protective layer on the surface of the core steel offers clean cut steel core protection Fast and Smooth Drilling --Creates a fast and stable drilling, you could drill smoothly with no broken edges Machine --angle grinder (Pay Attention! If you drill through thick granite ,we recommend you to add enough water to help cooling the bits,which could prolong the lifetime)