o 22 GPIO pins: 9 analog inputs, 21 PWM, 2 serial, 3 SPI, 3 I2C

o All GPIO is 3.3V but 5 volt tolerant

o 2 rows of 9 0.1 pins, with a third 0.05 row of 8 pins on the end

o On-board USB PCB Type connector, plugs right into any computer USB port

o Two on-board LEDs and one button

o STM32F401CDU6 CPU - ARM Cortex

o On-board 3.3v 250mA voltage regulator, accepts voltages from 3.5v to 16v

o Current draw in sleep: < 0.05mA - over 2.5 years on a 2500mAh battery

o On-board FET can be used to drive high-current outputs