Features: CUAV USB Expander Integrated Safety Switching / Buzzer / led Indicator / Multi-functional Integration Integration of safety switching, buzzer and LED indicator. Expand USB and C-RTK interface at the same time, powerful function. Convenient Connection: Provides multiple interfaces for users to connect different devices to meet diversified needs.Simple to operate, improving work efficiency by integrating multiple functions in one unit. Specifications: Item：CUAV C-RTK 9P Expansion Module USB Integrator Integrated Safety Switching / Buzzer / led Indicator Size：About 34x21x12mm/1.34x0.83x0.47in Package Includes: 1Set CUAV C-RTK 9P Expansion Module USB Integrator note: Due to problem of lighting effect and shooting, there might be tolerances in product, please understand. Please allow 0-1cm error due to the measurment.