1. A 1/8-in. TRS (Tip, Ring, Sleeve) connector that is typically used for connecting headphones to cameras and mixers, however, some mixers have a 1/4-in. TRS headphones connector, so its always good to have an adapter in your kit; 2. Some consumer cameras used a 1/8-in. TRS connector for microphone input. Sometimes these inputs provide 5V plug-in power, the consumer equivalent of phantom power.