No, there is no difference between the two TireMinder Trailer TPMS monitor models.
The TireMinder TRL-2, TRL-4, and TPMS-TRAILER models are the same in every quality except color of the monitor. Each of them have the same 1 year warranty period and use the same TireMinder Trailer TPMS transmitters and Trailer TPMS Signal Booster.
Minder Division of Valterra Products
3000 SE Waaler Street
Stuart, FL 34997