The SPC4 from AKG is a wide-band antenna combiner that combines the signals from up to four SST4 transmitters into a single signal. It has four BNC inputs and a single BNC output for connecting the transmitters and an antenna.

It has an easy-to-use front-panel interface with a power button, status LEDs, and a ventilation grill. The unit can run on a 12V power adapter (sold separately), or it can be connected to the PSU4000 power supply to power the SPC4 as well as any SST4 transmitters that are connected.