Duo is a thumb-size development board made to simplify the building process of Internet of Things (IoT) products. Everything you need is built into the Duo. It contains WiFi, BLE and Cloud, all in a compact form factor that makes it ideal for your first prototype, a finished product, and everything in between.
The Arduino Uno Wi-Fi is the new Arduino Uno with an integrated Wi-Fi module! The board is based on the ATmega328P (datasheet) with an ESP8266 Wi-Fi Module integrated (datasheet). It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz ceramic resonator.
It’s the Arduino Pro Mini! SparkFun’s minimal design approach to Arduino. This is a 3.3V Arduino running the 8MHz bootloader. Arduino Pro Mini does not come with connectors populated so that you can solder in any connector or wire with any orientation you need.