MSR E-Bivy 1 Person Bivy Sack Functional: Simple design helps slow heat loss and keeps you dry Reliable: Coated and taped Sil Nylon is more durable than "space blankets" and keeps you dry Ultralight and Small: Weighs only 7oz and small enough to bring anywhere Versitile: Keeps dew and frost off your bag if sleeping out and adds warmth