HEPAtech System Replacement Filter Permanently charged Electret filter effectively captures 99.97% of particles as small as 0.1 micron in size from the air that passes through the filter Use with Hunter Models 30201, 30212, 30213, 30240, 30241, 30251, 30378, 30379, 30381, 30382, 30526, 30527 and 30528