NATUREHIKE Ultralight Backpack (22L)
This is so compact and lightweight. Frankly speaking this can be use for anything. From hiking to shopping. 
These type of foldable bag has been my favorite. At time we can bring along as extra bag for a travel and most of the time this serve as the grab and go backpacks for morning hike. 
Best of all is that this lightweight back pack is water proof. From the "tent" material all the way to the YKK zip. The zip liner is design with waterproof as well. 

SPECIFICATIONS:
Color: Black

Capacity: 22L

Material: 3D Nylon

Size: 26 x 20 x 42 cm (Unfold)

Weight: 170 grams