Arduino compatible boads

It has an Atmega2560 chip running at 16Mhz with a factory loaded bootloader with 54 digital input / output pins (from which 14 can be used as PWM outputs) and 16 analog inputs, 4 UART (hardware serial ports).
The board includes a USB connector, an ICSP port, a reset button and some status LEDs. Atmega16U2 programmed as a USB-to-serial converter.
for power, simply connect it to a computer with a USB cable or power with a power adapter and DC connector.
ATmega2560 R3 REV3 16U2 Mega2560 module with USB cable features:

- Operating voltage: 5V
- Input voltage (recommended): 7-12V
- Digital I / O Pins: 54 (14 PWM outputs)
- Analog input pins 16
- DC current per Pin I / O 40 mA
- DC current per Pin 3.3V 50 mA

Nano V3.0 CH340 Soldering Plate + Arduino compatible USB cable features:
- Microcontroller: ATmega328
- Operating Voltage (logic level): 5V
- Input Voltage (recommended): 7 -12V
- Digital I / O Pins: 14 (6 PWM outputs)
- Analog Inputs: 8 (A0-A7)
- DC Current per Pin I / O 40 mA - Flash memory: 32 KB (2 KB used by the bootloader)
- SRAM: 2 KB
- EEPROM: 1 KB
- Clock Frequency: 16 MHz
- Communication USB - CH340
- Dimensions: 18mm x 44mm

It has an Atmega328P chip running at 16Mhz with a factory loaded bootloader.
The Uno R3 module has all connectors than the Arduino Uno R3 and is compatible with all Arduino shields.
UNO CH340 board + Pins + Arduino compatible USB cable features:

- ATmega328 16MHz chip with crystal external quartz
- Microprocessor: ATmega328
- Operating voltage: 5V
- Input voltage (recommended): 7-12V
- Input voltage (limits): 6-20V
- Clock speed: 16 MHz
- Digital I / O Pins: 14
- Analog input pins: 6
- DC current per I / O Pin: 40 mA - DC Current per Pin 3.3V: 50 mA
- Flash32 KB of which 0.5 KB are used by the bootloader -Atmega328
- SRAM 2 KB - Atmega328
- EEPROM 1 KB - Atmega328

- It has an Atmega328P chip running at 16Mhz with a factory loaded bootloader - The Uno R3 module has all the connectors than the Arduino Uno R3 and is compatible with all Arduino shields Arduino compatible UNO R3 board features:
- Includes USB Cable - ATmega328P 16MHz chip with external quartz crystal
- Microprocessor: ATmega328
- Operating voltage: 5V
- Input voltage (recommended): 7-12V
- Input voltage (limits): 6-20V
- Clock speed: 16 MHz
- Digital I / O Pins: 14
- Analog input pins: 6
- DC current per I / O Pin: 40 mA
- DC Current per Pin 3.3V: 50 mA
- Flash32 KB of which 0.5 KB are used by the bootloader - Atmega328
- SRAM 2 KB - Atmega328