ADAFRUIT INDUSTRIES 1756 ADAFRUIT LED SEQUINS EMERALD (1 piece)

Simply connect 3 to 6VDC to the + pin and ground to the - pin, and the LED on the board will light up. You can make the LEDs fade and twinkle by using the PWM (a.k.a. analogWrite) functionality of your Gemma or Flora, or just connect directly to a digital I/O pin of a microcontroller to turn on and off. Or even skip the micro altogether, and power directly from a LiPoly or coin battery. This order comes with 5 Emerald Green "1206 size" LEDs, matched with a 100 ohm resistor. When powered from 3.3V they draw about 5mA so you can put up to 4 or 5 in parallel on a single microcontroller pin.