The 25L Backpack Rain Cover has an elastic design and fits the PGYTECH OneMo 25L Backpack or similar backpacks. Made from waterproof polyester fiber, this cover prevents water from seeping into your bag. When not in use, it can be easily rolled up and stashed in the included small soft pouch. The pouch has a string so you can secure it to the exterior of your backpack so it's handy when you need it. The pouch also has a drainage hole that will release excess moisture from the rain cover so that it dries quickly once the rain has stopped.