This is the lowest priced solar oxygenator in the uk. However, don't be fooled by the low price tag as this solar air pump set includes a top class solar panel which will produce a maximum air flow of 100 litres per hour. Be quick this item always sells out!air pumps are essential for the health of your fish especially in the summer when oxygen levels are depleted. Additional air leads to additional water circulation and a healthier pond.the pondxpert solarair 100 is perfectly suited for the following ponds br • no fish 750 litres 165 gallons br • fish 550 litres 120 gallons br • koi 250 litres 55 gallonsaccessories included with the solarair 100 br • 1 x 4mm air line 2m br • 1 x 20mm air stonesolar powered the solarair air pumps are powered by the sun and contribute a good flow of air into the pond. No electrical installation required!please note this item works in direct sunlight only. If you want your solar pump to work when conditions aren't sunny then we have a leading range of battery back up solar oxygenators to choose from.