1,24 In. Portable Air Cooler, 2,high performance, 3,Cools 1, ... ft,/ 4, Variable Speed 5, Durable ,energy saving. 1)24 In. Variable Speed; 2)HIGH PERFORMANCE; 3)Cools 1,800 sq ... performance 1/3 h.p. variable speed motor.3. No need to install, portable, could be used immediately after connecting ... Somewhere there are polluted gas, population density and others where need ventilation. 24 In Swamp cooler