The Retevis RETC 15 RT22 is a UHF hand-held two-way radio walkie-talkie designed for communication in various settings. With 16 channels and a PMR service, this model is known for its reliable performance in transmitting and receiving messages. The loose used tested unit quantity of 1 suggests a single device that has been previously tested for functionality. This calling system from Retevis is suitable for use in radio communication scenarios, offering a practical solution for individuals or groups needing reliable communication on the go.