... drilling and long life 3, Full range of sizes Diamond core drill bits for concrete,wall,floor,masonry, dry use 1, Suitable ... .5mm, 2mm, 2.5mm, 3mm.7, All kinds of thread adaptors or connections in 1-1/4"UNC, 1 ... , M16, M42, CRI28 or PIXIE, etc.8, Full inspection of the adaptor size and concentricity by the most advanced inspection ... request. Diamond core drill bits for concrete,wall,floor,masonry, dry use