Guide hole saw or drill bit to drill clear holes on tile, glass, marble, counter-top, granite, etc Adjustable plates' maximum opening length is 3-1/4", large enough to put in all sizes' hole saws 4 removable bearings can be re-positioned at the 7 bearing holes depend on your needs Suction cup base has good strength to hold the centering jig tight and well on smooth surface Made of engineering grade ABS plastic, durable quality, not easy to get cracked Note: Need the hole drill used together!（No Hole Drill Included） Instructions: 1. Adjust the sliding plate for the size of the hole saw - drill bit you want to use. 2. Fix the guide using the suction base exactly where you want to drill the hole. 3. Using water as coolant, start the hole. 4. Use the guide until the drill bit - hole saw makes an initial mark deep enough to keep the bit in position. 5. While drilling, keep using water to cool down the diamond drill bit - hole saw.
