I bought this product after reading a couple of positive reviews on here and I really wish I hadn't.
Basically it is a piece of felt which you roll up and tie some elastic bands around on a tube when you're done. When mine arrived it was all creased and needed a good ironing first, but even so it's a poor excuse for a 'jigsaw accessory'. I've since bought the jigsaw caddy (kind of like a suitcase that opens out for you to do the jigsaw) which is definitely worth the few extra quid.
If you really think this is a good idea then buy a couple of metres of felt from a haberdashers, get three elastic bands and cut an old cardboard carpet tube! Job done for £2 ish.