LinkNode R4: WiFi relay controller 4-Channel Relay Module ESP-12f ESP8266 WiFi module 4-Channel Relay Module 7-28V DC power Two work modes Program via UART Boot from flash 4 indiator LEDs ESP-12f ESP8266 WiFi module 4 Channel relayssupporting: <ul class="a-unordered-list a-vertical"> 277V AC 10A 125V AC 12A 5V DC power Two work modes: <ul class="a-unordered-list a-vertical"> Program via UART Boot from flash 4 indiator LEDs