The Smart HO UV Sterilizer from Emperor Aquatics features high output T6 style UV lamps offering approx. twice the ourput as standard lamps. The housings have a 5 inch diameter, which along with the high output bulbs, allow for a higher wattage unit that takes up less space.For aquarium or pond use-For aquariums up to 500 gallons. The 500 gallons rating assumes the unit is being used as a clarifier (algae) and sterilizer.-For ponds up to 5,900 gallons50 watt T5 UV lampIn lineConnections: 2" union inlet/ 2" union outletA pump is a required. The required flow rates:-Algae: 1980 gph maximum, 1560 gph minimum-Protozoa: 720 gph maximum, 540 gph minimumDimensions: 28" X 5.75"NOTE: This item is drop-shipped directly from the manufacturer. We do not offer expedited shipping for this item.