Water can often be your heaviest piece of luggage on the trip. The CamelBak Lumbar Reservoir allows you to carry this weight on your hips instead of your shoulders. CamelBak has equipped the Lumbar Reservoir with a stability-enhancing compression system, as well as a side buckle that absorbs impacts on the hip. • Function: Hydration bladder to be worn at the hip • Purpose: Universally applicable • Material: Polyurethane • Weight: 180 g.