The Air Stream is a large sleeping pad pump, based on the 20 L Ultra-Sil Nano Dry Sack from Sea to Summit, enhanced with a valve and a foot strap. Thanks to the Venturi effect, you can inflate the Air Stream with a single breath. To fill a Sea to Summit sleeping pad, you only need two or three repetitions, allowing you to inflate the sleeping pad very quickly, with minimal breath condensation and without feeling dizzy. The Air Stream can also be used as a 20 L Dry Sack or as an Ultralight Pack Liner. Ultra-Sil is a very lightweight waterproof nylon fabric. The outer layer is surrounded by a silicone coating, while the inner layer is PU-coated.