Portable, battery-powered circuit monitor with alarms, dramatically reduces OS circuit, Shunt-Fouling testing time. Seven point shunt test can be completed in two minutes, fifteen seconds. Monitors track circuit voltage and alarms when track voltage drops below 0.1V. Works with all known types and brands of circuits used as OS circuits. Can also be activated by dry or powered relay contacts or floating outputs. Base of Rail Clamps can connect the “Friend” to the rail. Alternative Head of Rail Clamps are available. Alarms indicating circuit voltage dropped below 0.10V are 90dB sounder and 100,000 candlepower strobe light. Alarm format is selectable:  one or the other, or both. Settings are retained until changed, even if unit is powered down. Use with S&C Probe or Fast Shunts to further reduce testing time. Operating temperature range: -22degF to 140degF (-30degC to 60degC). Comes complete with Universal Charger and HD nylon carry bag. Kits with Base of Rail Clamp Connector Set listed below. Tripod for “Friend” also available.