I asked the factory some years ago and was told it was "isolation" or "mounting" tape. I made a few more phone calls and determined it was probably mylar electrical tape.

You can buy the mylar tape. It looks like clear packing tape except it is more expensive and it lasts a lot longer. 3M makes a mylar tape. It is hard to figure out which one is mylar. You will need to email 3M. If you know a Tornado sailor ask them. They use mylar tape to fair the ceneterboard gaskets.

You can use outdoor electrical tape. Your local electrical supply company will probably have some. You can paint the fitting with liquid electrical tape or bed it with any adhesive or caulk that is rated as an insulator.

I use mylar or flurglas tape mostly because I have it handy and it is easy to use.

I hope this helps