Drill straight holes quickly and easily with this diamond drill bit from Task Tools. Great for multiple drilling operations, the bit comes with a water cooling system for quick transitions from hole to hole with no wait for the bit to cool down. That means smooth drilling in glass, marble, stone and even class-5 porcelain. A handy drill bit guide sets up quickly for precise, perpendicular drilling and no walking of the bit. A diamond sintered edge ensures long bit life and faster drilling. Bit size: 1/2-Inch .