The SparkFun Qwiic Pro Micro is a revision of the original Pro Micro and is, overall, functionally the same as the previous version. The board is the same size as the original Pro Micro but we added a few additional features by shrinking down some components on the board such as a reset button, Qwiic connector, USB-C, and castellated pads (this makes it really handy for you custom keyboard creators out there). Think the Pro Mini except with an ATmega32U4 on board and full USB functionality.
The benefit of the reset button is to quickly reset the board or place it into bootloader mode without the need to take out a piece of jumper wire. The USB micro-b connector has been replaced with the USB type C connector. The through-hole pads have castellated edges for each pin to add a lower profile in your projects should you decide to build it into another assembly during production. Finally, a Qwiic connector is populated on the bottom of the board to easily add Qwiic enabled I2C devices to your projects.
Key Features

ATmega32U4 running at 5V/16MHz

AP2112 3.3V Voltage Regulator

Supported under Arduino IDE v1.0.1+

On-Board USB-C connector for programming

PTH Pads w/ Castellated Edges

9x 10-bit ADC pins

12x Digital I/Os (5 are PWM capable)

Hardware Serial Connections

UART (i.e. Rx and Tx)
Qwiic Connector for I2C
SPI

Small Arduino-Compatible Board

Reset Button

Dimensions: 1.3in x 0.7in

STEMMA QT / Qwiic 4-pin 1mm Pitch White Female Connector Cable 150mm Long – Both Sidecan be purchased seperately.
Resources

Schematic

Eagle Files

Hookup Guide

Board Dimensions

Graphical Datasheet

ATmega32U4 Firmware Notes

ATmega32U4 Datasheet

Arduino Comparison Guide

Arduino Board Add-on

GitHub Hardware Repo