... 3.20 years experience in drill equipment 1.Advantages of our products(1) strong resistance to abrasion and impact resistance ... Stocks adequate, time delivery.(5)Rich experience in drill bit.(6)High quality, competitive price2.Detailed product description IADC ... 8", 6", 6 1/2", 6 5/8", 7 1/2", 7 7/8", 8 1/2", 9 1/2", 9 5 ... 8", 14 3/4", 15 1/2", 16", 17 1/2", 18", 26"Cutter Sizes5/16" (8mm), 1/2" (13mm), 5/8 ...