Improve testing efficiency: seamlessly evaluate relay performance; green LED confirms functionality, red signals faults - easily track data and time. Perfect performance: this automotive relay tester is carefully crafted with excellent workmanship to ensure it is not easily damaged; made of high-quality materials, it is tough, sturdy, odorless and safe to use. Easy to carry: never miss any details when testing on the road. This relay tester is small and lightweight, perfect for outdoor diagnosis. Pack it in a convenient bag and easily test your electrical system at home or on the go. Great gift: make your loved ones' birthdays, Father's Day or even Carnival memorable with this relay tester automotive kit, and ensure their cars run safely and smoothly. Multiple applications: discover the ideal solution to effectively test a variety of automotive relays (including common types), while detecting and diagnosing faults with 12V sensors and battery voltage and vehicle battery power.