How the Ultima AC works is that the water that’s filled in it, soaks the water curtain. The air is then forced to go through the water curtain as it’s sucked by the fan, which cools it down. However, along with cooling, the air is also humidified as part of the process which makes this device a bit unsuitable for regions of high humidity. It’s best used in places with dry heat. The aforementioned water curtain also acts as a filter that blocks dust particles from coming out of the grille. This is why the water curtain has to be periodically removed to be cleaned. The cleaner air is routed via the 3-speed fan towards the adjustable grille. The speeds of the fan can be adjusted via a button on the top of the device. Cooler, Filter, and Humidifier all in one package. Almost silent operation. Ultima Portable AC comes at a cheap price with a limited time discount.