Made of 100% Polyester, this raincover makes your backpack waterproof from the points where it covers. Extremely lightweight and folds inside it's own pouch and can be hanged or inserted in backpack. This is not only compatible with alpinebear bags but with also other company bags. Dimentions of both size pouches are here. Large Size dimentions are 45x33x14 and XL size dimentions are 48 x 33 x 19. Only avaiable in Green color which help recongize person on bike or on road while it's blury in fog or rain.