These Aviom A - 16II personal mixers come in a pack of 4. They don't include external power supplies, but can be easily powered through the network.

Using these Aviom A - 16II personal mixers is straightforward. First, connect them to the network for power as they don't come with external power supplies. You can then start using them to mix your audio. When using, make sure the network connection is stable. As for maintenance, keep them in a dry and clean place. Avoid exposing them to extreme temperatures or moisture. If there are any issues, check the network connection first.