1、When the board is connected to the PC and the PC is restarted, the relays will be toggled several times. This is because of the structure of the FTDI chip 2、The device must be supplied with 12 VDC to work 3、Extra PCB openings for better voltage isolation 4、Doubled high current tracks 5、There is no protection against reversed voltage! If the VCC(+12V) and GND are reversed the board will be damaged Features: When the board is connected to the PC and the PC is restarted, the relays will be toggled several times. This is because of the structure of the FTDI chip. The device must be supplied with 12 VDC to work. Extra PCB openings for better voltage isolation. Doubled high current tracks. There is no protection against reversed voltage! If the VCC(+12V) and GND are reversed the board will be damaged. The board can not work without computer. Specifications: Relay: 10A 250VAC/10A 125VAC/10A 30VDC /10A 28VDC Power Supply: 12VDC Current Consumption: 300mA Size: 93*70*16mm/ 3.66* 2.75* 0.63" Software Examples: VB6, BCB6, Java (netbeans), VB.NET 2010 Express, C++.NET 2010 Express PCB: FR4/ 1.5mm/two layers/metalized holes/HAL/white stamp/solder mask Package Includes: 1x 8-channel 12V USB Relay Board Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.