As part of the ZeroNoise Pit-Link kart trainer / communication system this wearable micro amplifier features noise canceling for optimum communication clarity. Small enough to attach to your suit or helmet via a velcro patch or even wear around your neck on a necklace this amplifier connects to a smart phone via bluetooth to enable clear communication with the pit crew. Suitable microphones, in ear speakers and pit crew headsets are all available to purchase separately.Small and lightweight ideal for kartingCan bee attached to a suit or helmet using Velcro or can be worn around the neckNoise cancelling provides clear communicationPlease note: A separately available microphone and in ear speaker kit are required to enable communication along with a smart phone.