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 Sea to Summit sleeping pads. With two to three cycles of air, your sleeping pad will be inflated with minimal condensation on the inside of your pad, leaving you with no dizziness from puffing. The lightweight 15D Ultra-Sil dry sack is large enough to store clothes, or a sleeping bag inside your backpack.