This thing is a worthless piece of junk. Do not waste your money.
The battery never holds a charge and must be charged for at least an hour before every use. The battery fails to lock in to the tool correctly, so I have to tape it in place to get the tool to work, even though I've only used it 3-4 times. It is hopelessly underpowered for any real sanding or grinding, and has failed to work effectively on any project I've tried it on yet. It wouldn't cut a brass toilet bolt, couldn't even grind a 1/16" groove in a lock hasp.
It might be good for a kid to play with, but I have yet to find a job it could do.
Review about: Dremel Cordless Rotary Tool.
Monetary Loss: $28.