Liquidating my BIL'S auto tools,gadgets. I don't know how to test but I do know if he had a tool it was in working condition ALWAYS! Fast shipping, The Snap-On Digital Timing Light MT2261A is a high-quality automotive diagnostic tool perfect for ensuring accurate ignition timing. Manufactured in the USA by Snap-On, a trusted brand known for durable and reliable tools, this digital timing light offers precise measurement and display of engine timing. With its sturdy plastic mold construction, this unit is designed to withstand tough use in professional automotive settings. Although it does not come with a warranty, its reliable performance makes it a valuable asset for mechanics and car enthusiasts looking to optimize engine performance.