REI brand, titanium-grey backpack cover for 40L pack. Used only a handful of times for commuting; selling because it's the wrong size for my current bag. Still fully waterproof - no tears or snags! Asking $15, original price $24.95 (see https://www.rei.com/product/118867/rei-co-op-ducks-back-rain-cover-40-liters for similar). Pick up in midtown Palo Alto or can deliver to campus.