For all you DIYers and mechanics out there, this green LED tachometer is a seriously handy tool for measuring RPM speeds! The 4-digit display shows clear, bright numbers that are easy to read even in well-lit workshops. It measures from 10 all the way up to 9999 RPM with impressive ±0.1% accuracy, which is plenty precise for most applications. The package includes everything you need - the tachometer itself, a 3-wire NPN Hall proximity switch sensor, a round magnet, and connecting cable. It works with a wide 8-24V DC power range, making it compatible with various systems and vehicles. The Hall sensor is NPN normally open type and needs to be within 10mm of what you're measuring for accurate readings. The 0.56-inch LED digits refresh 3 times per second, giving you real-time feedback without lag. Installation is pretty straightforward if you follow the wiring diagram - just make sure to keep measurement wires away from strong electromagnetic interference for best results. The compact size (about 3x1x1.7 inches) makes it easy to mount in tight spaces. Whether you're working on small engines, industrial equipment, or custom projects needing precise RPM monitoring, this tachometer delivers reliable performance without breaking the bank. The green display is easy on the eyes during long work sessions, and the build quality feels solid enough for regular use. It's one of those tools that once you have it, you'll find all kinds of uses for monitoring rotational speeds in your projects.