The Filter Alarm (Smart Alarm) from Polylok is a wired indoor/outdoor filter alarm that activates when the filter cartridge is near capacity (approximately 90 percent full) of solids buildup. The switch, installed in the filter, sends a signal to the alarm panel, activating the audible and visual alarm to alert the home or business owner of necessary service. It has a manual alarm test switch and horn silence, alarm horn rated at 82 dBA at 10 feet, and 15 feet of cable (with longer lengths available). It will fit Polylok, Zabel or Best filters. 800/701-3946; www.polylok.com.