1. Onboard and stable ESP-12F module, large capacity 4MByteFlash 2. The module's I/O port and UART program download port are all led out to facilitate secondary development 3. Onboard DC power supply circuit, power supply mode supports DC5V/12V/24V, power supply power should be higher than 20W 4. Onboard reset button and IO0 programmable button 5. ESP32/ESP8266 supports for IDE compilation tools, providing reference programs under for development environment 6. Onboard 32-way 5V relay, output switch signal, suitable for control, working voltage is within AC250V/DC30V load 7. main control replaceable design (The product appearance and printed words depending on the batch, but this does not affect use) Material: PCB colour: Package Contents: 1 x Relay Module Only the above package content, other products are not included. Note: Light reflection 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.