Except for the pin 51, everything else works just fine. As we're selling this limited quantity at half price, it's a good bargain, as long as you don't need that faulty pin.
Specifications:
    Microcontroller: ATmega2560
    Programmer: CH340G
    Clock Speed: 16 MHz
    Operating Voltage: 5V
    Input Voltage (recommended): 7-12V
    Digital I/O Pins: 54 (of which 15 provide PWM output) - pin 51 is defective, not connected to the microcontroller!
    Analog Input Pins: 16
    Flash Memory     256KB (of which 8KB used by bootloader)
    SRAM: 8 KB
    EEPROM: 4 KB