1. On-board mature and stable ESP-12F WIFI module, large 4M byte flash capacity.2. The WIFI module input / output port and UART program download port are all led out to facilitate secondary development;3. RST Reset button of built-in WIFI module.4. ESP-12F is compatible with development tools such as ECLIPSE / IDE.5. 2 to 5V relays, output switch signal, suitable for controlling AC working voltage Charge within 250V / DC30V.Integrated power indicator, 1 programmable LED and relay indicator.colour: greenMaterial: PCBsize: 78x47mmPackage Contents:2 x ESP8266 ESP-12F WIFI Relay ModuleOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.