Meet the warmest mattress in Therm-a-Rest’s NeoAir collection. The XTherm features multiple ThermaCapture layers to provide four-season warmth without adding weight or bulk. A new WingLock Valve system maximises airflow for faster setup. When inflated, 6.4cm of cushioning gives reliable comfort; when deflated, it takes up about as much room as a water bottle. It's an excellent choice for ultralight backpacking, alpine bivvies and mountaineering trips.