(1) Electromechanical 7 digit counter The Model DARC is an optional, 7 digit, electromechanical customer counter that simply plugs into the built-in 12 volt out put jack included on all of our Model DARD receivers. This optional accessory provides customer traffic flow tracking into stores or fitting rooms for planning employee hours and space utilization of fitting rooms. The electromechanical function of the keeps the counting results even if the receiver is unplugged from the power. The counting results of the retail people counter cannot be reset, therefore eliminating accidental data loss. The DARC can operate with the audible function of the Model DARD, or can operate independent without any audible (silent mode).