... 17 1/2", etc. IADC Code:4-- Series, 5-- Series, 6-- Series,etc. 2. Elastomer sealed bearing ... 17 1/2", etc. IADC Code:4-- Series, 5-- Series, 6-- Series,etc.3. Air Cooling Roller ... 315 316 317 325 327PDC BIT(3 blades,4 blades,5 blades,6 blades)5 1/2, 6 1/27 7/8 ... ,8 1/2,8 3/410 5/8, ... M122 IADC437517537617637737WOBKN/mm (bit dia.)0.5-0.750.5-0.850.5-0.850.55-0.850.55 ...