HEPA-GELTM is an anti-gravity, self-healing sealant material. It is an excellent alternative to more commonly used neoprene gasket. It can be used horizontally or vertically and in forward or reverse channels. The ceiling grid system or filter housing must have a corresponding knife edge flange which seats itself in the gel channel. HEPA Corporation also manufactures filters utilizing knife edge flanges for ceiling grid systems or housings which have a gel channel instead of a knife edge. Both styles are available with all frame materials.