This series connectors including 6.35mm JACK to RCA Adapter, RCA to RCA adaptor and RCA splitter. They  were used for connecting a cable with RCA connectors to a device with a 1/4″ Jack input (guitar lead input) combiner, for instances where an RCA cable (TV, CD player, DVD, Xbox), needs to be connected to a 1/4″ input. Two of these adapters could be used to plug a Left/Right RCA output, such as can be found on a DVD player or DJ mixer, into two line inputs on a main mixing desk, or directly into two powered speakers.