I bought two for only 4.84 euros in total. it was worth it. There I see the price just went up from 2.82 to 7.27 euros each! This is illogical. well worth the price I bought (2.82 euros) and I am very satisfied, I would take the other end. Well see over time if it gathers dust well and well see if the price will rebaisser. They are fixed to both fans of my external 240mm radiator water cooling.
However, I wonder if there is a way to magnetize these gates with an electric cable to increase the electrostatic attraction of the grids, which allow to attract all dust particles as small or they, that'd be great.