The ESP8266 Thing is a breakout and development board for the ESP8266 WiFi SoC – a leading platform for Internet of Things (IoT) or WiFi-related projects. The Thing is low-cost and easy to use, and Arduino IDE integration can be achieved in just a few steps.

We have no idea what USB device you are hooking up to, but if you want to access the microUSB port on something, you might want this.

The SonoffRFR2 is a Sonoff version with an integrated 433MHz RF receiver module. This product can be used in conjunction with an RF remote control, which allows you to control appliances indoors.