The package arrived before expected. The Copper Stuf-fit was easy to work with by using your fingers or a screw driver to stuff it in cracks to prevent entry of mice. I would recommend this company to friends.
It appears to be working. I won't know until I am sure it has kept the critters out for good. I used it for my outside air conditioning unit, to block the entrance of critters. I wanted something that would not rust (steel wool was an option, but it does rust). This seems like it will do the trick, and it is still in place. To me that's a good sign, unless they found another way in!