We have the manufacture factory, making productions and selling by ourselves. So we can control the quality of our productions by ourselves for you. We'd like to receive your valuable suggestions for our products and make your idea come true.This version is optimized in the original version , mainly for customers under the functional requirements for product quality and high case designed both to ensure consistent and compatible with the original, but also easy to use.Operating Voltage: 5V Input:Voltage(recommended) :7-12V Input Voltage (limits) : 6-20V Digital I/O Pins: 54 (of which 15 provide PWM output) Analog Input Pins: 16 DC Current per I/O Pin: 40 mA DC Current for 3.3V Pin: 50 mA Flash Memory: 256 KB of which 8 KB used by bootloader SRAM: 8 KB EEPROM: 4 KB Clock Speed: 16 MHz Use 5.5 * 2.1mm DC barrel jack (compatible with 5.5 * 2.5mm DC barrel jack)Package includes: 1 x Mega R3 Board 1 x USB cable