This is a 3.3V Arduino running the 8MHz bootloader, in a very small package - a Mini Arduino, you might say!
This is LilyPad Arduino, the heart of a wearable electronics system! This main board features a ATmega328 preloaded with Arduino, and is ready to connect to a wide variety of wearable, sewable modules!
The Pro Micro is similar to the Arduino Pro Mini except with an ATmega32U4 on board. The USB transceiver inside the 32U4 allows us to add USB connectivity on-board and do away with bulky external USB interface.