Multi-Functional Rucksacks Waterproof BagBackpack or Sling Bag: the sling bag could be used as a sling backpack after unzipping the single strap into 2 straps, or zip them together, you can use it as a chest bag and diagonal bag when you zip it, and you can use it as a backpack when you open the zipper. Durable Material: The women's sling bag is made of high quality waterproof fabric, which is dirt resistant, strong and not easy to tear. This sling bags with smooth zipper for durable use.