Load of crap or actually useful?

Self-fusing tape has been around awhile. It works. the idea is that it's a silicone tape that will bond to itself when stretched and allowed to recoil. Not always the easiest thing to apply, but all of those claims are entirely possible for silicone. Note that it does take a few minutes to 'set up', which the infomercial manages to neglect.

6 rolls for $20 is actually a pretty good deal, too. Most of the time it's a minimum $5/roll.

In the Air Force we call it F-4 tape. The old guys used to tell us that in Vietnam most of the hydraulic systems on F-4s were patched together with the stuff. Last year at MAM we replaced our PCV neck with a piece of hose wrapped in F-4 tape. It does turn into a gooey mess when subjected to heat and oil, but it will still do its job. Great stuff!

We use that kind of tape all the time for sealing up electrical and RF connections.

The 700 PSI thing seems a bit far fetched.

Good stuff though (assuming the product advertised is high quality).

The military uses this stuff for insulation on electrical connections. I think that's where it is really meant to be used. It does self seal, and does provide lots of electrical insulation. Not sure about the rest of the claims. I've never used it for anything else. The real Mil-Spec stuff is way more expensive, like $20-30 a roll. This might be worth checking out for a few dollars.