Awhile back I received a bad pack of cartos from FSUSA. I sent them back and they replaced them with a different kind. However, the new ones are bare metal. I hate the way they feel and with no "insulation" around them, they can get too hot. I've tried a carto condom with a hole in it, over the end and didn't like that. I also tried wrapping painter's tape around them, which helps but is a pain in the ..... Although I'm sold on the juices from FSUSA, they can keep their cartos. These are the probably the worst cartos I've ever tried.