George,
Sorry, I missed a whole bit out of my last post. To post the comment fully...
Yes Rhynogrip is great stuff, it sticks to the hooks on the inertia sander very well, it's got a good abrasive coating, but it's paper backed. A strong paper grade but still paper.
Cloth backed abrasives are far better for what we do, they are more flexible, J weight abrasive is still a low grade of cloth backed abrasive available. There are better ones.
As David says, the packs of abrasive strip from Axi are cloth and there was a cloth abrasive very popular before Rhynogrip (and inertia sanders) arrived, I seem to remember it to be Hermes or something like that, but I've never seen a cloth backed abrasive with a looped backing (prepared to be proved wrong on this of course).