Yep... as far as I can tell they are all but indestructible. I've ridden my MTB (26x2.0" Plus tyres) over all sorts of stuff and never flatted. One time out on a ride with a group of friends we'd covered 150 miles in two days and about half of the group had had at least one puncture. I'd pulled things like an inch-long thorn out of my tyre and just thrown them in the hedge or the canal.

One other point about them, they are much harder than regular tyres to put on and take off, so if you are using them make sure you've got levers. They will also make your ride harsher as they won't give as much as regular tyres.

They do typically have reflective rings around them which seems like a nice touch, and if you want something with more tread try the Plus Tour. If you want the tread but a lighter tyre try the Extreme. It lacks the plastic lining but seems pretty resilient to flats (not tyres as previously written.... d'oh!).