ATmega328 running at 16MHz with external resonator (0.5% tolerance) Low-voltage board needs no interfacing circuitry to popular 3.3V devices and modules (GPS, accelerometers, sensors, etc) 0.8mm Thin PCB USB connection off board Weighs less than 2 grams! Supports auto-reset 3.3V regulator Max 150mA output Over current protected DC input 3.3V up to 12V On board Power and Status LEDs Analog Pins: 8 Digital I/Os: 14 0.7x1.3" (18x33mm)