The RB-PMX4 is a high performance 10 mono input to 4 mono output pre-set mixer. Each of the four outputs has a 10 way DIP switch associated with it to select which of the 10 inputs are routed to it.So,by altering the DIP switches, any of the input sources can be mixed to any of the outputs.The DIP switches are enclosed by a screw-on cover on the front panel so that the settings can not be accidentally changed for secure applications.