Review on Complete Hole Saw Kit With Diamond Drill Bits And Adjustable Guide Jig For Glass, Ceramics, And Tile - 15 Pieces, 6-50Mm Size Range by Duane Kaul

The jig worked as advertised, kept the hole saw lined up exactly where I wanted it to be, no walking or sliding. The diamond hole saws, however, are lacking. They are too shallow (short) for most kitchen countertops. They might be ok for bathrooms though. I managed to drill 1/4" into my countertop using water for cooling and dust control before the diamond dust was worn off the holesaw. When they say 1/2" maximum thickness, they mean it.