Completely waterproof protection for your pack that compresses into a tiny stuff sack and deploys quickly when you need it most. We recommend purchasing the larger size if you're on the fence. For instance if you have a 75 liter pack we recommend you purchase the Extra Large instead of the Large. If your pack is under 30 liters take a look at our High Visibility Raincover. Extra Large - Fits 75-110 liter packs. Large - Fits 50-75 liter packs. Medium - Fits 30-50 liter packs. Ultralight Raincover MD