These are new Atmel
ATmega328P-AU parts programmed in our U.S. facility with the
Arduino Uno or Due bootloader. Please specify which bootloader you prefer when ordering. If no preference is specified the device will ship with the Due bootloader.
We also offer other AVR devices with an Arduino bootloader, e.g. ATmega1284P, ATmega644P, and ATmega2560.
A 16MHz crystal and suitable load capacitors for it as well as other circuitry is necessary to make an Arduino device using this chip. Information is available in various places on the Internet about how to do this.