HGLRC SPECTER 15A ELRS AIO 2-4S 4-in-1 AIOThis is an F411 15A 2 4S ELRS AIO integrated brushless flight controller that includes UART serial ports and on board ExpressLRS 2. 4G. Compared to the SPI receiver, the integrated UARTS serial port receiver offers better performance and signal stability. Additionally, it eliminates the limitations of the SPI receiver such as limited functions, complicated setup, and short signal distance. The integrated serial port ELRS receiver also solves the issue