It will work with any Towmate that has a red antenna wire on the transmitter. Examples are the TM36, TM48, TM21, etc. With the iMon Monitoring System you will never have to worry about losing your lights again with our easy to use interactive monitoring System. Operates with any system equipped with iMon electronics. Purchase with a new unit or upgrade your existing one easily to work with the iMon. Monitor the functions of your light bar (LEFT TURN, RIGHT TURN, STOP, and HAZARDS), be alerted when you leave your light bar behind (signal Strength from wireless light bar), and monitor the battery level of your light bar all with one easy to use device. Simply plug your iMon into your vehicle's cigarette lighter and be 100% aware of your wireless light bar abilities and location. * If purchasing an iMon, back up lights are not available on the light bar in which the iMon is being used. * Does not work with TM22G or TM22Y models.