This waterproof cover by WOYYHO is made entirely out of waterproof nylon material. The cover can resist a hydraulic pressure of 2000 MPa so it won't let a drop of water in!
The exterior layer adopts wear-resistant nylon to avoid scratches and dirt. The inner layer has a waterproof coating applied to avoid rain and snow. The cover has an elastic fabric and band so it can stick to the backpack and avoid falling.
The cover can be easily folded and tucked away in your bag when it's dry outside.