The Outdoor Research Lightweight Pack Cover provides waterproof over-pack protection. This pack cover is made of lightweight HydroLite™ fabric with a waterproof coating. The seams are taped to prevent moisture from seeping through on long, wet days on the trail and an elastic drawcord at the edge creates a tight seal around a pack of any shape. When the sun finally comes out, it packs down for storage in the built-in stuff sack.