Diamond Drill Bit 5pcs 6-12mm+Cross Hole Opener Drilling Ceramic Quick-fit Shank

Item: BGTEC Diamond Drill Core Bits Set Quantity:  5pcs/Box (4pcs Diamond Drill Bits+1pc Positioning Hole Opener) Connection: Quick-fit Shank,shank diameter 6.35mm Package: Plastic Box Specification and Application ·Diamond Drill Bits 1) Segment material:Diamond coated 2) Specification: Drill Bit: Diameter 6/8/10/12mm,Segment height 8mm,Total length 65mm;Grit#50/60 Cross Hole Opener 1) Segment material:Hard alloy 2) Specification:Diameter 6mm,Segment height 12mm,Total length 77mm; Diameter 8mm,Segment height 14mm,Total length 79mm Diameter 10mm,Segment height 14.5mm,Total length 82.5mm 3) Note:This cross hole opener is to provide accurate positioning for diamond bit, not for drilling! Feature:  1.Use the cross hole opener first to position the hole and pre-drilling,make drilling more precise and easier. 2.Quick-fit shank,fast and convenient,suitable for hand drill,bench drill... 3.Vacuum Brazed technology,high quality diamond coated,faster drilling and better finish quality. 4.Wa