This is a small (approx. 31 x 40 x 5 mm) ESP32 development board. It's a simple and easy-to-use board that can also be developed with Arduino. Many pins can be used. The inner pins are compatible with the WeMos ESP8266. Multiple units are available. The price is 800 yen each for the second and subsequent units. I will prepare a dedicated listing, so please contact me in the comments.