[For ESP8266 ESP-12E]: It is fully compatible with ESP8266 ESP-12E. [GPIO 1 into 2]: This expansion board can expand one GPIO pin of Development Board to two, which is convenient for users to reuse pins for large-scale smart home projects. [2 Type Connections]: Two connection methods: Pin Header Connector & Screw Terminal. Just select them according to your purpose. [Double-Layer PCB]: The expansion board is a double-layer board. One pin is wired on both sides. Therefore, the circuit is stable and highly reliable, and there be no poor circuit contact and unstable signal transmission. [Updated Version]: Compared with the previous version, the board of this version has been soldered completely. No need to solder parts by yourself, which is very convenient to use. Colour: green Material: plastic Package Contents: 2 * ESP8266 Breakout Board Only 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.