Self inflating mat
Self inflating mats are a step above a roll mat.
They are basically a very thin air bed with a bit of foam, the layer of air in them gives some insulation from the ground making for a comfortable nights sleep.
The mat comes rolled up and packed down tiny. In theory...you undo the valve, unroll it and leave it for a short while and it inflates it self, you then give it a few puffs and it's fully inflated. In real life you just blow it up like a balloon until it's hard enough and shut the valve.
Much like sleeping bags there are loads of brands, however there is a king brand, Therm-a-rest. They are the people who developed the technology and the people who make the best mats still today. They cost a small fortune but have a very good life time guarantee, something no other manufacturers seem to offer.
Alpkit make some know as erics, they offer a really good nights sleep until they leak which normally happens within 2 years. They are also about half to a third of the price of a Therma-A-Rest original, so they are worth keeping in mind!