Dual Bak-Pak Hang-On Protein Skimmer by CPR Aquatics. **** PRODUCT MANUAL **** CPR has taken the proven technology behind the BAK-PAK™ 2, and created the NEW BAK-PAK™ Dual Pak. The Dual Pak provides a complete hang-on filtration unit for tanks up to 100 gallons that incorporates two protein skimmers with a biological filtration chamber in the middle. Using proven Rejuvenation Venturi technology, the protein skimmers are flooded with bubbles for constant removal of excess organics. The biological chamber utilizes CPR's Bio-Bale™ biological filter media to provide maximum surface area for beneficial bacteria to colonize. Simply hang on BAK-PAK™ Dual Pak on the back of an aquarium, plug in the rejuvenation venturi powerheads, and enjoy a worry-free operation! Dual Bak-Pak Specifications: * Body Size: 11-1/2" wide, 3-3/4" deep, 18" height * Recommended for aquariums up to 100 gal.