I work a lot with tiles. Lots of showers and bathrooms. I'm tired of sometimes spending up to $40 on tile drill bits to set fasteners in the wet areas of these projects. Just a glass shower door needs 8 screw holes in the tile to hold it in place. The drill bits I bought from big stores would do for maybe 2-3 holes and then I would have to use another one. These beats I bought here were 10 for the price of one at Menards. The first bit I used was enough for all 12 holes I needed in my last shower. This has never happened before. Outstanding quality.