The Beta 87A with the SLX2 transmitter features the BETA87A supercardioid condenser microphone head which gives you studio quality sound and is tailored for lead vocals for live performance. It also provides maximum isolation from other onstage sounds. The SLX2 Wireless Handheld Transmitter includes a timed backlit LCD display, frequency and power lockout and "Mute" functionality. This transmitter requires the SLX4 receiver to complete the system. All Shure wireless transmitter designs allow for interchangeable microphone heads.