Welcome to our store! 1. Blue Backlight: The screen of this LED handheld tachometer displays the maximum measured value with a blue backlight for easy reading, offering great convenience. 2. Simple Operation: This propeller speed tester is easy to use. Simply turn on the switch, select the number of propeller blades, and aim it at the rotating propeller from a distance of about 2 to 3.9 inches to start reading. 3. High Accuracy: This digital tachometer has a small error margin and high accuracy, making it suitable for RC aircraft, channel, and propeller speed testing. 4. Durable Material: This RC drone tachometer uses premium ABS and electronic components, ensuring it's robust, durable, and has a long lifespan. 5. Comes with Lanyard: This digital RC tachometer includes a lanyard, is lightweight, and easy to carry. Simply hang it on a hook or shelf for convenience. Item Type: LED Handheld Tachometer Material: ABS Application: Suitable for Drone Propellers Battery: CR2032 x 1 220mAh Built-in Battery: CR2032 x 1 220mAh Working Mode: Photoelectric Highest Reading: 99,999 Display Mode: LED Number of Propeller Blades: 2 to 9 Automatic Shutdown: 1 minute without signal Backlight Color: Blue 1 x LED Handheld Tachometer 1 x Battery 1 x Lanyard Customers are our top priority. If you encounter any issues with your product after receiving it, such as damage or incorrect quantity, please contact us immediately. We strive to provide you with the best after-sales service.