Ever have air bubbles in your wax but they weren't air bubbles, they were water bubbles? Water collects in compressors and, unless controlled, will end up in the wax pots and in the wax. The Shor Desiccant Filter removes the water before it can enter your wax injector. Just put the filter in your air line and you're all set. One desiccant filter is sufficient to handle 1-2 injectors.