The 12V Power Supply unit is a dedicated unit to maintain the brightness of the LED PANEL due to the physical phenomenon of voltage drop when low voltage units are connected in series. With the screw type easy connector, the 12V Power Supply is easily positioned to give enough power from 4 to 8 LED PANEL.LED PANEL Size Number of LED PANEL per 12V Power Supply Unit30cm x 30cm 8 pieces30cm x 60cm 4 pieces60cm x 60cm 4 pieces12V Power Supply (SDL-109P) IS ALSO SUITABLE TO RUN OTHER LED PRODUCTS