What are the Arduino micro and Pro micro board?

What are the Functions of the Pro Micro Pinout? - RAYPCB

The case of the broken Pro Micro (reprise) – gr33nonline

With ATmega32U4, running at 5V/16MHz. Supported under IDE v1.0.1. 12 x Digital I/Os (5 are PWM capable). Rx and Tx Hardware Serial Connections.

diymore Arduino Pro Micro 16MHz 5V with 2-Row Pins Header Module Board ATmega32U4 Module Board Micro USB Pro Micro Development Board Microcontroller

Pro Micro & Fio V3 Hookup Guide - SparkFun Learn

Pro Micro ATmega32U4 Board 5V 16MHz Compatible with Arduino Pro Micro ATmega32U4

Introduction to Arduino Pro Micro - The Engineering Projects

PRO Micro Atmega32u4 5V / 16MHz Mini MCU Leonardo Board for Arduino - China PRO Micro, Atmega

New Pro Micro for arduino ATmega32U4 5V/16MHz Module with 2 row pin header For Leonardo in stock . best quality - AliExpress

Arduino Pro Micro (Clone) Not Recognizable - IDE 1.x - Arduino Forum

Introduction to Arduino Pro Micro - The Engineering Projects

Part: Arduino Pro Micro (Clone) - parts submit - fritzing forum