Specification: _x005f_x000D_ Origin: Mainland China _x005f_x000D_ Color: Black Green _x005f_x000D_ Material: PCB _x005f_x000D_ Style: _x005f_x000D_ A: Expansion board _x005f_x000D_ B: Expansion board+development board _x005f_x000D_ PCB material: high-quality FR-4 material _x005f_x000D_ PCB layers: 2 layers _x005f_x000D_ PCB thickness: 1.6mm _x005f_x000D_ Size: About 6.35x6.3x1cm/2.5x2.48x0.39inch _x005f_x000D_ Weight: 30g _x005f_x000D_ _x005f_x000D_ _x005f_x000D_ Note: _x005f_x000D_ Due to the different monitor and light effect, the actual color of the item might be slightly different from the color showed on the pictures. Thank you! _x005f_x000D_ Please allow 1-2cm measuring deviation due to manual measurement. _x005f_x000D_ _x005f_x000D_ _x005f_x000D_ _x005f_x000D_ Included: _x005f_x000D_ 1 x Expansion board _x005f_x000D_ Or _x005f_x000D_ 1 x Expansion board _x005f_x000D_ 1 x Development board 1. Increased Flexibility: The module is fully compatible with the ESP8266 ESP-12E development board and allows users to expand the GPIO pins of a single board into two, making it extremely convenient for large smart home projects that require the reuse of pins. 2. Versatile Applications: The module is safe and reliable and can be extended to various applications, making it an ideal choice for users seeking flexibility in their designs. 3. Double-Sided Design: The expansion board features a double-sided design with pins on both sides, enabling users to connect multiple devices simultaneously. 4. Superior Stability: With high stability and reliability, the module ensures seamless operation of your project without any disruptions.