Detachable Holding Tank: 2.6-gallon holding tank is detachable for easy emptying. Prevents Leaks and Odors: Holding tank seals firmly to prevent escaping leaks and odors. Pump Flush: Fresh water holding tank uses a pump flush action to effectively rinse the bowl of the toilet; Flush Capacity: 4-gallons. Durable Construction: Made of durable ABS resin. Size: Measures 13 5/8-inches (H) x 16 5/16-inches (W) x 18 5/8-inches (D); The outside width of the seat measures 12 5/8-inches the inside width is 8 13/32-inches.