Esp-12 development board
This is an adapter board that can be used to flash ESP-12 modules before adding them to a device.
Using ESP-12 modules instead of using full featured boards like nodemcu is especially suitable for creating devices that run on battery or low power conditions and therefore do not need USB chips.
When using this kind of adapter with a EPS-12 module the solution behaves like a regular nodemcu board, same Flash size, same CPU etc.