1. performance: Onboard ESP01 WiFi module and performance microprocessor STM8S103. Board mode selection and realtime work status display. Reserved UART debug interface and STM8 SWIM download interface. 2. The relay has two operating modes: Mode 1: The phone is directly connected to the WiFi module. Mode 2: Both the phone and WiFi module are connected to the router. Other features: It can also function as a USB relay switch when the ESP01 is removed. 3. Transmission distance: In an open environment, when the phone is connected to the WiFi module, the maximum stable transmission distance is 100 m. When both the WiFi module and phone are connected to the router, the transmission distance depends on the router's signal strength. 4. Advanced functionality: Uses SmartConfig technology to configure the account and password on the mobile app for the ESP01 WiFi module, with username and password memory function.