PORTER 's signature series, Tanker, has been reborn using 100% plant-based nylon, the world's first material to be successfully mass-produced. The Sling Bag Double Zip features an attractive, simple design and is equipped with a variety of interior pockets. The pockets are carefully placed down to the smallest detail, and are designed for ease of use. There is also a pocket on the back, making it convenient for storing and taking out your smartphone and other personal items.