Used for distributing stereo or mono audio signals to and from devices. Applications of laptop and desktop computer audio I/O output, Pro audio distribution, projectors, and IR (infrared) signal transmission. Sold in carton increments only, with each carton containing 25 individually bagged keystone connectors. X = housing colors BK (black), EI (electric ivory), GY (gray), SF35SJ (office white), TI (telco ivory) and W (white).