Product Name: Vacuum Brazed Diamond Drill Core Bits Sets Hole Saw Mixed size Quantity: 1set/7pcs boxed drill bits Contains:5pcs(20/35/40/50/68mm) drill bits and 1pc 20mm finger bits and 1pc hex shank adapter, totally 7pcs/box; Specification: 1, core bits: Dia 20/35/40/50/68mm; M14 connection;total length 60mm; diamond height 15mm; 2, finger bits: Dia 20mm; M14 connection; total length 65mm; workable length 50mm; grit #50/60; 3,The Hex adapter : M14 male thread, 3/8" hexagon shank, shank length 28mm, total length 53mm; Feature: Dry or wet drilling Having wide application: for porcelain tile granite marble stone masonry brick All bits are produced in vacuum brazed technology Vacuum brazed technology provides longer working life, fast and smooth drilling Less chipping, minimizing breakage, less heat generation, better finish quality ===============end======================