Thermarest U24 NeoAir XTherm NXT MAX Pad

With cutting edge Triangular Core Matrix™ construction and ThermaCapture™ technology, the full-rectangular shaped XTherm NXT MAX delivers a 7.3 R-value while weighing just 680 g (24 oz) in the Large size. Put another way, the best warmth-to-weight ratio of any rectangular sleeping pad ever created.