Storage by day, pump by night. The Air Stream Pump Dry Sack features a low profile valve that connects to the multi-function valve on all of our sleeping mats – Air Sprung Cell mats and Self-Inflating mats. Used with an Air Sprung Cell mat, two or three cycles are enough to inflate the mat while adding minimal condensation. With a Self-Inflating mat, the pump will ‘top off’ your mat quickly and efficiently. The lightweight 15D Ultra-Sil dry sack is large enough to store clothes or a sleeping bag inside a backpack.