I have the slipon version, and it does a couple of things... one protects my hand after I shoot it, I can take it off, drop it in my bag and not think twice about it. Second, it keeps the heat signature of the can from making noticeable mirage when shooting.. I've shot this in the summer and after 20 rounds, I don't notice any mirage off the can.
^^^^^^ this. Customer service and wait time completely sucks however.
Gemtech Outback II.Pat
You might have a hard time finding a cover for a rimfire can.