Product Review

Kit includes:

Circuit Playground Express - Developer Edition
USB cable - A/MicroB - 3ft
3 x Alkaline AAA batteries
3 x AAA Battery Holder with On/Off Switch, JST, and Belt Clip
Mini Storage Box

Here's some of the great goodies baked in to each Circuit Playground:

10 x mini NeoPixels, each one can display any color
1 x Motion sensor (LIS3DH triple-axis accelerometer with tap detection, free-fall detection)
1 x Temperature sensor (thermistor)
1 x Light sensor (phototransistor). Can also act as a color sensor and pulse sensor.
1 x Sound sensor (MEMS microphone)
1 x Mini speaker with class D amplifier (7.5mm magnetic speaker/buzzer)
2 x Push buttons, labeled A and B
1 x Slide switch
Infrared receiver and transmitter - can receive and transmit any remote control codes, as well as send messages between Circuit Playground Expresses. Can also act as a proximity sensor.
8 x alligator-clip friendly input/output pins
Includes I2C, UART, 8 pins that can do analog inputs, multiple PWM output
7 pads can act as capacitive touch inputs and the 1 remaining is a true analog output
Green "ON" LED so you know its powered
Red "#13" LED for basic blinking
Reset button
ATSAMD21 ARM Cortex M0 Processor, running at 3.3V and 48MHz
2 MB of SPI Flash storage, used primarily with CircuitPython to store code and libraries.
MicroUSB port for programming and debugging
USB port can act like serial port, keyboard, mouse, joystick or MIDI!