ATmega328P-PU DIP-28 pin Microcontroller with Arduino Uno Rev3 Bootloader Free shipping and the pinout sticker is included This microcontroller can be used to an existing Arduino-compatible board or standalone Tested with Arduino IDE in Mac, Windows, Linux and it is compatible with these OS Includes an Atmel ATmega328P-PU 8-bit AVR microcontroller loaded with Arduino Uno bootloader Rev3 The ATmega328P-PU is loaded with the blink sketch too