In reply to Andes, samsimpson:
I've got an original gold 4 Season Karrimat from the 1970's, which I still use all the time.
I've now cut it in half for Alpine climbing, it's indestructible and only weighs 160 grams.
It's so tough that I've used it on many alpine bivvies, while rock and ice climbing, often huddled or jammed on small rough rock ledges with very little damage.
I've got several other foam mats, including a later Karrimor salmon pink model from 1980's, none of them are anywhere near as tough as my original Gold Karrimat.
It really doesn't tear, scrape or puncture though the edges were nibbled once in a Scottish bothy so not perfect!!
I wonder if anyone now manufactures mats in the same foam, which compared to most newer mats is quite stretchy and rubbery?
Cheers Ron