I don't understand all the comments about the cordless drill not working. It works just fine! I cut four holes in the ceiling for the surround speakers (I chose this model because Sonos' architectural speakers require an 8-1/4" cut-out) in about 5 minutes. And it worked great with my Dewalt 20v cordless drill. You need to turn it fast and cut it slowly (maybe 10 seconds in drywall). But there is no mess and the hole is perfect! I highly recommend this tool!