The USWE Race 2. 0 Hydration Pack is a super lightweight hydration bag meant for cross-country and trail riding and one of the most efficient ways to tote around water on longer rides. The main fabric of the Race 2. 0 Hydration Pack is made of recycled polyester for eco-friendly construction, and the back panel and the harness system are made out of polyester mesh for airflow. USWE's No Dancing Monkey 1. 0 Pro harness system ensures a bounce-free fit that stays stable on our back, provides optimal aerodynamics, and weighs in at a measly half-pound weight. The included 2-liter Elite hydration system has a magnetic hose attachment at our chest for easy hydration on the go, while the zippered compartment on the rear of the bag stores the hydration bladder and has a small pocket for our phone and keys.