The SEALED TireMinder TPMS-TRL-4 Double Axle Trailer Solar Tire Monitoring System is an easy-to-install wireless system that monitors tire pressure for trailers. It includes a signal booster and can be placed on the rear, front, left, or right side of the vehicle. The system does not require any programming and uses high-quality tire pressure monitoring sensors to ensure accurate readings. With its solar-powered design, this system provides peace of mind for trailer owners by alerting them to any potential tire issues before they become dangerous.