Was skeptical purchasing used. Item arrived quickly and packaged well. Drilled four 5/8" deep hole and found that slower speed worked better. Created a dam for water keeping drill cool and lubricated.
This is a very good quality hole saw! I use them to drill glass bottles an other containers , and they last very well even with the different thickness of the bottles and containers. It's also at the best price I could find anywhere!!!!
While constantly cooling with water I used the diamond hole saw on slow speed to drill through stone and after drilling many holes it's still as good as new!