CPR CS90 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. CS90 Specifications: * Flow Rate: 600gph * Outflow Size: 1" Bulkhead * Width: 7.25" * Dimensions: A: 7", B: 8.5", C: 1 3/8", D: 1.5", E: 4 3/8" , F: 5", G: 8.75", H: 5 7/8", I: 3 3/8", J: 2.75", K: 3.75"