Because the day before I had finished a thorough cleaning of the room, I found it really surprising when I tried it for the first time and found that it still worked. I do not have any regrets about making the purchase, as I am happy with it. Got pros: Really, it's extremely peaceful here. Strong ability to draw in air. Compact. assemble and disassemble are two steps in a process that make technological sense. Cons: It is not common practice to modify the suction power by sliding a flap along a tube that one holds in one's hand. This is one of the device's drawbacks. The absence of an additional engine speed control circuit is a benefit, despite the fact that this is a negative from a purely technical standpoint.