Quantity   Component name
2 × Arduino Uno
2 × Gravity: IO Expansion Shield
2 × Gravity: Analog Audio Sensor
2 × AMP386 Audio Amplifier
2 × 6xAA Battery Pack w/ Barrel Jack Connector
2 × NRF24L01+PA Module
2 × Tactile Switch (Pushbutton)
2 × A Tin Can!