... adequate, time delivery.(5)Rich experience in drill bit.(6)High quality, competitive price2.Detailed product ... Diameters4 5/8", 5 7/8", 6", 6 1/2", 6 5/8", 7 1/2", 7 7/8", 8 1/ ... 2", 9 1/2", 9 5/8", 11 5/8", 12 ... 1/4", 13 5/8", 14 ... "Cutter Sizes5/16" (8mm), 1/2" (13mm), 5/8" (16mm), 3/4" (19mm), etc.MaterialAlloy steel, carbideFormation ...