4 black & white composite monitors in a 3U 19" rack module. Single power cable. All work fine.
These have a BNC input but I have some BNC to RCA adapters for with them, any common composite video device (retro game consoles, VCRs, laserdisc players, video cameras, home security recorders, etc.) can drive them.
Bought for an art project but never got around to doing it. Need to let some stuff go.