The T-50K is a professional impedance matchng transformer that allows a low impedance microphone (100-600 0hms) to be connected to a high impedance input (10k-50k 0hms)
A typical application for the T-50K would be if one wanted to plug a low impedance microphone directly into the high impedance input of a guitar amplifier for either vocals or harmonica.
In this case, one would plug the XLR-male connector of the microphone cable directly into the XLR-female connector of the T-50K. The 1/4" connector of the T-50K then would plug directly into the input of the guitar amplifier. Note that the cable is allowed to hang freely from the connector in order to reduce the strain of the 1/4" jack of the T-50K as it is plugged into the guitar amp.
The T-50K may be used with long microphone cables helping to prevent loss of signal, loss of frequency response, and extraneous hum or noise.