Description of Osprey UL Raincover Lightweight and Waterproof Backpack Cover Available in four sizes and incredibly light and packable, the UL Raincover will keep your gear dry in the darkest of deluges. Features: XS: 600-1200 cu. in. (10-20 liters), 3.75oz (.10kg) S: 1200-2400 cu. in. (20-40 liters), 4oz (.11kg) M: 2400-4300 cu. in. (40-70 liters), 4.25oz (.12kg) L: 3600 up cu.in. (60 up liters), 4.5oz (.13kg)