Smog-Hog Kitchen Emission Control System electrostatic precipitation (ESP) is the key to Smog-Hog's superior performance. It's a sophisticated electronic solution that leaves no grease or smoke particle untouched. Unlike bag filters,which provide mechanical solutions that remove only the largest particles, ESP electrically charges even microscopic contaminants then captures them, magnetically, in an aluminum collection cell. Maintenance is simple because Smog-Hog's aluminum collection cells are easy to clean and reuse,eliminating the costs associated with filter replacement and disposal.