... UL SGS IP54 Ultra-thin filter not only can be used as a air inlet for clean air in low ... temperature, but also as the air outlet for heat load, non-woven fiber filters are used to ... blade, has greatly improved its appearance. No need bolt for Installation, just embedding it is ok, its protection grade ... can reach IP54 level. This series are suitable for models of fan: 172*150*51,200*200*60,220*60