The System 9 Frequency-Agile VHF Wireless System Receiver from Audio-Technica is a single-channel receiver, although it is a frequency agile system. This means that you can select any one of the four frequencies (169.505, 170.245, 171.045, and 171.905 MHz) and use up to four System 9 wireless systems at the same time, if each system is set to a different frequency.

This receiver is designed to provide rock-solid performance and can be used when paired with a bodypack transmitter or a handheld transmitter and microphone (sold separately) for capturing audio in sound reinforcement applications.

Furthermore, the receiver is equipped with an advanced dipole antenna for extended operating range, which improves operation by providing a ground element in addition to the usual signal element. The ATW-R900a offers volume control along with AF Peak, RF, and power indicator lights.