The UM400 is a rugged, machined aluminum pack age with a removable, spring loaded belt clip. The input section provides a correct input tap for virtually any microphone or line level audio source. Five volts of bias voltage is available to power electret mics with either positive or negative bias. Level indicating LEDs are provided on the control panel to make level settings quick and accurate, without having to view the receiver. The battery compartment accepts any 9 Volt alkaline battery and makes a positive connection via self-adjusting contacts. The antenna is a detachable, locking 1/4 wavelength flexible galvanized steel cable that connects to a 50 Ohm SMA port on the transmitter.