The Polylok Inc. / Zabel Filter Alarm (Smart Alarm) is a wired indoor/outdoor filter alarm that provides audio/visual warning for home or business owners that their tank filter needs cleaning. The Smart Alarm Switch activates when the filter cartridge is near capacity (approximately 90 percent full) on solids that have built up through the filtering process. The switch, which is installed in the filter, sends a signal to the alarm panel, activating the audible and visual alarm and alerting the home or business owner that the filter needs servicing. The alarm includes a manual alarm test switch and horn silence, as well as an alarm horn rated 82 decibels at 10 feet. It comes with a 15-foot cable with longer lengths available. 888-765-9565; www.polylok.com