Compcooler UniPack ICE Water Circulation System includes a 2.5L Dual chamber hydration bladder, Flow control pump and a rechargeable battery COMP-UPCS-7425-H-FC Operation Manual for Hydration Bladder The Compcooler UniPack ICE Water Cooling System (UPCS) combines a dual chamber backpack with an integral tubing-lined liquid cooling channel liner into one self-contained and convenient thermal regulation device. The liquid circulation system is an attached backpack which contains a 2.5L removable water bladder, circulation pump, rechargeable battery and On/Off switch. Cooling energy is provided by freezing the water in the bladder. This is easily accomplished by removing the bladder from the system using quick-connect fittings, and then placing the bladder in a freezer. Once frozen, the bladder is easily re-attached to the system using the quick-connect fittings. With a charged battery pack, Users turn the switch on and the pump circulates cold water in a continuous loop between the bladder and cooling channel. With the included 3.0L bladder, Users can expect a cooling duration anywhere from 2-4 hours depending on ambient temperatures and workload. Additional bladders and battery packs can be purchased for prolonged cooling. Component List 1. UniPack Cooling Unit Integral Circulation System: 2. Hydration backpack Dual chambers 2.5L (1) 3. Battery 7.4V 2200mAh (1) 4. Battery Charger (1) 5. Pump Unit, ON/OFF Mode (1)