Features: 3901 L0X Traversing Machine Optical Flow Meter: This product is designed specifically for Fixed Wing optical flow meter, providing precise positioning and high stability. Lidar sensors: Equipped with lidar sensors, it can perceive the surrounding environment in real time and provide more accurate obstacle avoidance and collision avoidance functions. Flight control fixed height hovering: Compatible for F4 7 flight control system, it can achieve reliable fixed height hovering function and provide a stable flight experience. High precised optical flow meter: using high-precised sensors and algorithms, it can provide accurate position and attitude information in complex environments, achieving stable flight control and hovering capabilities. Multifunctional sensors: In addition to the optical flow meter function, it also integrates lidar sensors to detect and avoid obstacles, providing safe and more reliable flight protections. Easy to install and adjust: The product has a compact size and rich interfaces, making it convenient for users to install and adjust. It also supports common flight controlled software, making it convenient for users to adjust parameters according to their needs. Specifications: Material: Printed Circuit Board Size: approx. 36x13mm/1.42x0.51inch Hole Distance: approx. 30.5mm/1.2inch Note: Before starting the flight control, ensure that the distance between the sensors and the ground is greater than 2cm/0.78inch. Please allow 1-2cm errors due to manual measurement. Please allow for slight color differences due to different display resolution. Package includes: 1x MATEK 3901-L0X Optical Flow Sensors Module