A double balanced mixer has a DC detection circuit connected to receive the output of the mixer core. An appropriate amount of special thread 4 comprising a core thread 5 having a high melting point and a core-thread covering skin 6 having a low melting point are added to the zephyrs and kneaded together. A digital-to-analog converter converts the digital output into an analog output. The first and second ends comprise first locking features. A consumer profile associated with the consumer is stored in a database and comprises a plurality of profile data items.