Hepa filter mycology for laminar flow hood 12 x 24 x 5.8 mushroom lab use. H14 hepa filter 99.995% efficiency at. With a 99.995 % efficiency at. 3 microns this filter will screen out those pesky trichoderma particles. 9 and the filters size is 24x12x5.8.The air flow direction leaves the black foam gasket side of the filter. In other words, the side without the black foam should be the side receiving air from your blower. H14 filter for mushroom lab work. In stock in the us. One 12 x 24 x 5.8 included in sale. Note other filter sizes are available and shown in photos.