CPR CS100 SIPHON AQUARIUM OVERFLOW BOX by CPR Aquatic. **** Overflow Box Selection Chart **** **** PRODUCT MANUAL **** A built-in overflow is the most efficient method of draining aquarium water to a filter. If your aquarium does not have built-in overflow, CPR Continuous Siphon Overflows/Prefilters are the best means for getting water from an aquarium to a filter system without expensive modifications to the tank. They quietly skim up to six times more water than units with tubes. The advantages of CPR Continuous Siphon Overflows/Prefilters include: * Adjustable water level allows you to easily change the level in your tank. * Black top reduces algae growth. * Plastic screen to prevent fish loss. * Quiet operation. CS100 Specifications: * Flow Rate: 800gph * Outflow Size: 1" Bulkhead * Width: 9 3/8" * Dimensions: A: 7.5", B: 9", C: 1.75", D:1 3/8", E: 4.5" , F: 5 1/8", G: 9.25", H: 6", I: 3.25", J: 3 1/8", K: 3.75"