Looking for the perfect blend of low weight comfort and warmth the sea to summit ultralight large insulated mat could be everything you d ever dreamt of the comfort side of things is handled by a single layer of 225 independent air sprung cells which conform to your body shape and the terrain you are sleeping on these air cells operate in the same way as a pocket spring mattress so you can be sure you ll get a great nights sleep wherever you end up every cell is filled with thermolite insulation