When you need protection in wet weather, the ultra-compressible Rainfly cover is your best friend. Made from 200D siliconized ripstop nylon, the Rainfly is stored in an integrated carrying pouch. The pouch connects securely to the external attachment points of Peak Design's Travel Backpack 45L, and fits neatly into an external sleeve. Outside, you can instantly deploy the Rainfly while it's still connected to your backpack.