EZBIO20 Size: 20 Double - Up to 3400 GPH Features: -Provide space for beneficial bacteria to colonize helping to improve overall water clarity. -Max Pump Flow: 1,980 GPH (11). -Max Pump Flow: 3,405 GPH (20). Product Type: -Filters. Generic Dimensions: -4 5/16 x 7 7/8 (11). -8 x 7 1/2 (20). Dimensions: Overall Height - Top to Bottom: -7.8 Inches. Overall Depth - Front to Back: -8 Inches.