Use with LED's up to 3V. Each panel (7 rows, 5 columns of LED) has it's own potentiometer to regulate current, allowing you to mix and match the LED's used between panels.
Front of the badge - note that you should only mount the LEDs you want to light up (saves time, money, fiddley-ness).Note the 10 pin DIP is actually a set of DIP switches, and the 3 legged through hole potentiometers are missing in the 3D model.