TowMate TM22 Transmitter. 4 PIN Round.

This Standard 4-PIN Round Transmitter from TowMate is used on TowMate Tow Lights that do not use an external antenna. This transmitter does not have an antenna and the electronics are injection molded to ensure that it will resist the elements. If you are purchasing a transmitter for an existing light, you will want to match the wire colors of the transmitter and receiver. A red wire indicates the newest and most current series of electronics & will work with the I-MON monitor; a green wire indicates an older style prior to the series of electronics (Doesn't work with I-MON).