Milliard Solar Water Heater Fits 1-1/4in to 1 1/2in flexible hose fitting and works with your existing filter pump. 2,500 BTU/hour thermal capacity per unit powered by free energy that requires no wires or electrical installation! Multiple solar heaters can be connected in tandem to increase heating efficiency. (e.g.: A 1000 gallon pool would take about 17 daylight hours to heat with one heater, but could be heated in just under four hours with four heaters working together.) Simple installation with included hoses and stainless steel hose clamps. Includes protective cover for when unit is not in use.