... StructureThe durability of premium tungsten carbide inserts is improved with new formulas and new techniques ... 6",6 1/2",7 1/2",8 1/2",9 1/2",9 5/8",9 7/8",12 1/4",17 1/2", ... high rotary speed. 4. All-rubber compensator is used which can limit pressure differential and prevent ... perform consistently in high speed drilling applications, and is the ideal tool for drilling directional and horizontal ...