Commodore Amiga 520

With for instance the Amiga 500, video will only come from an Amiga video port, rendering it incompatible with a standard monitor or television set.   In order to be to use a standard TV, this device, the Amiga 520 was sold created.
One end plugs into the standard Amiga video port and the other end has both a composite video port, and a RF-modulated female port for televisions, along with a high-low channel selector.  There is also a connector for audio to be mixed in.