The OSEPP Uno R4 Plus board is the most popular Arduino board out in the Arduino market! This board uses the 8-bit, AVR, RISC-based ATmega328P microcontroller from Atmel.
Brand name(s) : OSepp

For use with Arduino experimenter kits

Return / exchange policy : Due to the "experimental" application use of this product, this item is not returnable. Unopened / shrink wrapped only.

Features:
8-bit AVR RISC-based microcontroller running at 16 MHz
Connects to a computer via a standard USB cable
Flexible power source (USB or DC power)
ICSP header for programming microcontroller
Compatible with existing Arduino software libraries
Compatible with all Arduino shields make for Arduino UNOs.

New features in R4:
• ATMEGA 16U2 Chipset
• Micro USB connector
• 4 additional 5v and GND power pins
• Additional analog pins A6 & A7

“Plus” Features:
• Replaced mini-USB connector with the more popular micro-USB connector
• removed the Molex connector

Specifications:
Microcontroller ATmega328P
Clock Speed 16 MHz
Flash Memory 32 KB
SRAM 2 KB
EEPROM 1 KB
Operating Voltage 5V
Input Voltage 6-12 V
Digital I/O Pin Count 14 (including 6 for PWM output)
Analog Input Pin Count 8

Other Connections:
micro-USB
ICSP for ATmega328p
DC power connector
4-pin latchable I2C connector

Dimensions 2.95 x 2.13 x 0.61 inches (75.0 x 54.0 x 15.5 mm)
Power Source USB or external DC power supply