As other users have stated about this tool, there is a safety issue with this product. There is no washer or nut to prevent the hole saw from snapping off the drill bit! When I cut a hole in the ceiling with this drill, I lifted myself off the ceiling while the saw continued to rotate under centrifugal force. He completely detached from the drill and took off like a flying saucer with sharp teeth. My reaction was to grab him in the air to keep him from falling onto my new floor. My teeth cut my fingers when I caught it! The only way to prevent this is to make sure the saw comes to a complete stop on your material before you pull it out. And do not start the hole saw in contact with your material. Absolutely dangerous. Attention buyers.