... ) value of double impeller air blower is only 2 or 3 points lower than single impeller air blower, the high-frequency noise of ... 1.threaded Outlet with handle 2.threaded Outlet, horizontal installation 3.Heating device selecting: without heating device(2),Application 1 hydromassage ... .52.62.2 -2.57620-407.510 spa heater air blower CE,FCC,CCC,TUV,UL,ETL