HiLetgo 3pcs Nano V3.0 ATmega328P CH340G 5V 16M Mini USB Micro Controller Board Development Board for Arduino with PIN Headers Pin Unsoldered Using Atmel Atmega328P-AU MCU, Support ISP download,using the same chips ATmega328P and CH340 with the official version. Support USB download and Power. Support for external 5V~12V DC power supply, Support power supply by 9V battery. You can learn more about how to use the item on the link: http://kiguino.moos.io/2014/12/31/how-to-use-arduino-nano-mini-pro-with-CH340G-on-mac-osx-yosemite.html Arduino Nano V3.0 ATMEGA328P improved version with 3pcs pin headers. No welding needed.