This is not a “tool” but really good stuff. GOOP. My wife picked it up at our local hardware store. I used it again today and it is just what the label says: AMAZING.
The cap looks like any other clear silicone tube, so it must be what’s inside. No matter how many times we use it (and how poorly she usually puts the cap back on) the stuff is always clear, and clean when I go to use it. It never dries out in the tube, and never plugs up the end.
And, it’s very sticky. Today the large gasket that sits up above the “bucket” on our central vac unit dropped off. A few dabs of this and it went right back up in the well. Dried quickly and the gasket never dropped. Great product. If you can find some locally, try it. You won’t be disappointed!