These are very interesting 5mm diffused RGB LEDs - instead of having 4 pins to control 3 LEDs, they have only two leads - power and ground. When powered, the LEDs perform a flashing effect with all the colors. They're fairly bright LEDs and they do diffuse nicely so you can the color changing from any angle. The forward voltage of the whole LED is about 3.4VDC but you can drive them from a lithium coin cell like a CR2032 and they'll just be a little dimmer.