A replacement collar cap, easy to grip. Tested on a Milwaukee M12 Rotary Tool, which since it fits Dremel attachments, means this should fit a Dremel too. (No promises, please leave a comment if you find out for certain.)
Rev 2 is purely aesthetic improvements.
Rev 3 looses the threads up so it's easier to get on and off.
The author marked this model as their own original creation.