[For ESP8266 ESP-12E]: Fully compatible with ESP8266 ESP-12E. [GPIO 1 to 2]: This expansion board can extend one GPIO pin on the Development Board to two, conveniently allowing users to reuse pins for large-scale smart home projects. [2 Types of Connections]: Two connection methods: Pin Header Connector & Screw Terminal. Choose the one that suits your needs. [Double-Layer PCB]: The expansion board is a double-layer board. A pin is connected on both sides. Therefore, the circuit is stable and highly reliable, preventing poor circuit contact and unstable signal transmission. This version's board is fully soldered. No need for self-soldering, making it very convenient to use. Color: Green Material: Plastic Dimensions: 63x63x9mm Package Content: 1 * ESP8266 Expansion Board Note: Light reflection and different displays may cause the color of the item in the picture to differ slightly from the real thing. The allowable measurement error is +/- 1-3 cm.