I am very impressed with this tool. I used a cordless drill to cut through a 5" thick window sill. This hole saw cuts 2.5" deep, I used a long 1/4" pilot bit as a guide first. You must run this tool at high speed, don't use the low speed, high torque setting on your drill bit or it will get stuck and get caught in a trap that will make it difficult to manage rather than run it at high speed and let the tool do its job , it will cut really fast found the pilot hole and continued cutting until it