This worked exactly as expected on a ceiling tile laid over 3 layers of drywall countertop. I used a large to medium sized clear party tray lid, drilled through the center to keep dust out. Make sure everything is tight before you start, apply very little pressure and take your time. The first hole for the 8.25-inch speaker was cut in 15 seconds at low speed, 10 seconds to suck a tile, then move on to the next tile. I spent more time making the dust cap but I was looking for the cheapest tool to save the school. money and party trays everywhere Got a tray cover for free from Wally World that explains what it is for.