Electroplated diamond core drill bit with Sharper edges ensures Fast & Efficient drilling performance: ... High speed,Smooth cut. Electro-plated diamond core drill bit (hole saw) :-Fast, clean and efficient way to ... stone(1). Diameter: from Ø3mm to Ø127mm(2). Shank/Top: Round, Trigonal, Hex (3). Diamond grit: D427, D252, D181 and ... with or without center pin. Diamond core drill: round shank