The Model 2491 (Single function), Model 2492 (Dual function), and Model 2493 (Triple Function) Digital Switchboard Meters were developed to provide customers with a versatile AC digital power meter. End user programmable for CT ratios and PT ratios. End user selectable legends Watts, kWatts and mWatts, etc. Non-volatile memory. If loss of power occurs, all settings will remain the same.