Lululemon Run All Day Backpack 13L in excellent condition. The Lululemon Run All Day Backpack 13L is a water-repellent backpack that is designed for running. It has an ultra-lightweight harness, adjustable sternum strap, and 360º reflectivity. The backpack also has side pockets, pockets on the harness, and a quick-access phone pocket. The pouch, lining, and body of the backpack are made from 100% polyester, while the contrast is 89% nylon and 11% elastane.