I bought these and they look nice and pretty so I enjoyed using them. Garbage! I used them to drill through 3 different pieces of glass. The thin glass just cracked. The thicker glass took about 35 minutes to fully pierce the hole (and believe me the glass wasn't thick enough to last that long) and cracked inside as it leaked. I've used it on ceramic and because it has lateral lines on the drill, it caught on the ceramic when I pulled the drill back through the hole and ripped the ceramic. Very dissatisfied with the claim they make