The rain fly provides complete weather protection for your already water-proof travel backpack. The Robin to your Batman, so to speak.

If you'd like to know exactly how to wrap it on or other tips, here's a demonstration:

Skip ahead to what you really want to see: 

• Attachable loops to the backpack (0:47)
• Wrap it around (1:24) 
• Synch cord (1:41)
• Material (1:57)
• PRO TIP (2:43)