These filters are custom made to fit the 120mm fan vents on the NCASE M1 case, as well as the Silverstone ST45SF PSU vent. This set consists of a 4-pack 120mm sqaure filters, and 1 x Silverstone ST45SF PSU filter. It can be ordered individually or as a 2-pack, 4-pack or a set. These filters come with the extra peel-and-stick magnets for non-ferrous surfaces. For more illustrations of this filter, click on the specs tab.