Heavy duty flexible bladder forms to back of user when filled, and is protected within a durable nylon bag. The Smokechaser Pro is designed to offer the most comfort in the grueling conditions of fire control. This backpack pump offers more storage and comfort than any fire pump bag made by Indian. Easy fill, 4” cap with two handles to help user balance bag while filling. Equipped with the all brass Fedco pump – approved by US Forest Service and known the world over for its quality and dependability.