ESP8285 ESP 1 - SmartArduino/SZDOITWiKi GitHub Wiki

The ESP-1 is also based on ESP8285. So, it has the same features as ESP-M1 and ESP-M2. For example, it can bear a much high temperature to 125℃, small size, and completely comaptible with ESP8266. So the programmed ESP8266 code does not change anything, and can be originally used on ESP8285 modules. The pictures for ESP-1 is shown as the followings.

The manual can be download from this link.

Now, this board can be ordered at many online shops, like Aliexpress, SmartArduino and banggood.