Internet service providers like AOL recommend changing the filters before they reach a year of service.
Electronic filter | Digital filter | Cherry Filter | Air filter | Photographic filter | Ohne Filter | Kalman filter | digital filter | Water filter | water filter | Shiva amplifier chains showing spatial filter tubes (white) and Nd:glass amplifier structures (short blue tubes closest to camera). Portions of the 1982 Disney film ''Tron | Sand filter | Probabilistic data association filter | Oil filter | Neutral density filter | Klaus Filter | Fram (oil filter) | elliptic filter | CSS filter | Cast Iron Filter | Band-pass filter | air filter | Adaptive filter |