Dwyer solid plastic gages and other gages are available in kits especially developed for air filter gage service. They include the gage, two static pressure tips with integral compression fittings ad two 5 foot lengths of ¼" aluminum tubing. The static pressure tips are installed in the duct upstream and downstream of the filter and connected to the gage to provide a continuous visual indication of the static pressure drop across the filter. When the filter's resistance in terms of static pressure drop reaches the maximum specified by the filter manufacturer, it is an indication that the filter should be cleaned or replaced. Complete details on Dwyer air Filter Gage kits and their use is given on pages 36P to 40P.