The Sena PI Universal Communication System turns your favorite outdoor-sport helmet into a Sena smart helmet with 2-way Bluetooth intercom. A compact headset, PI’s design makes it easy to attach to most cycling or skating helmets, or any other helmet with a strap width of up to 18 mm (0.7 in). Device operation utilizes a two-button layout located on the left speaker. Just clip the Sena PI to your helmet straps, hold the buttons to turn on the device, and #RideConnected!