Sun Moon 25L-40L Waterproof Reflective Backpack Rucksack Cover for Hiking Camping Traveling Blue. Reflective stripes provide high visibility. High-quality, waterproof backpack cover - strong and lightweight to help make you visible and keep your backpack dry. Perfect for the avid adventurer. Suitable for camping, traveling, climbing, riding etc. Suitable for most 25-40 liter backpacks or pannier bags.