The Polylok Filter Alarm (Smart Alarm) is a wired indoor/outdoor filter alarm, which provides audio/visual warning for home or business owners that their septic tank filter needs cleaning. The smart alarm switch activates when the filter cartridge reaches about 90 percent full of solids built up during the filtering process. It has a manual alarm test switch and horn silence, an alarm horn rated to 82 dBA at 10 feet, and 15 feet of cable (with longer lengths available). It is specifically designed to fit Polylok, Zabel or Best filters, ensuring proper placement of the switch. 877/959-7751; www.polylok.com.