— fans (see "Product type"), the casing thickness of which does not exceed 20 mm. This feature can come in handy when there is a small amount of free space — for example, in compact cases or in powerful systems with an abundance of “hardware”. However note that a small thickness reduces efficiency, and this disadvantage has to be compensated either by an increase in diameter (which affects the dimensions and price) or an increase in speed (with a corresponding increase in power consumption and noise level).
