Product Contents: The package contains 1 trailer plug tester, a reliable trailer tester connector that serves as a core tool for maintaining your trailer's electrical system. Quality Material: Crafted from quality plastic, this 4-way flat trailer circuit tester is built to be robust. The material provides protection against daily wear and impact, ensuring long-lasting performance for all your trailer wiring checks. LED Design: Equipped with bright LED indicators, this trailer light tester offers clear visual feedback for quick troubleshooting. The LED lights clearly show the status of different circuits, allowing you to easily identify issues with your trailer wiring harness at a glance. Easy to Use: Our 4 pin trailer plug tester features a simple installation. Just connect the trailer plug 4 pin to the corresponding connector, operate your trailer's lights, and observe the LED indicators. Wide Application: This versatile trailer tester is compatible with most 4-way flat electrical systems, suitable for testing trailers, trucks, campers, boats, and other vehicles. It efficiently checks the functionality of tail lights, turn signals, brake lights, and more, ensuring your trailer wiring harness works properly. Specification: Color: black Material: plastic Product Size: 4.9x3.3x1cm/1.93x1.3x0.39in Package details: Note: Due to manual measurement, the size and weight may have a certain error. Due to the difference between different monitors, there may be a slight color difference existed. Package Contents: 1 x trailer light tester Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.