Stranger bullshit, the blade keeps unscrewing from the drill bit, doesn't really fix securely and wants to swing in all directions, plus it's not compatible with the dust collector on drywall. I bought a replacement Kobalt hole saw from one of the larger stores that snaps in and is compatible with dust bags. It worked great and was about a dollar more expensive than this one. best hole saw for the same price, it's a terrible design and not worth it.