Terrible product. The spindle lock engages when it wants to, and my thumbs tensed trying to push down to unlock. Just when you think it's blocked, it's not. Everything was fine, I did a test run and luckily I heard him hitting the protective case. One more thread and the sanding plate would have come loose and killed me. I'm not an idiot who doesn't understand power tools. My friend just tried it, same thing. I will be returning it and would not recommend anyone to buy this tool. Definitely buy big names for a few bucks more, your life is worth an extra 20 bucks