Genlocks were one of the Amiga's strengths. With one you could overlay the Amiga's graphics over your telly or video productions. They even found their way into TV Production studios; in the 80s such programmes as ITV's 'The Chart Show' used Amigas to generate the overlays for each video they showed, since there wasn't an anchorman on the show. Many people will still remember the familiar pointer running round the screen to bring up tour news, gossip, facts etc about the band.

This is a Dutch genlock, so if it wasn't for the fact that the box says 'genlock' and it's plug-in module for the CDTV has video-in, video-out and SVHS out I'd be a bit stuffed as to what it did :)