The ZeroNoise Pit-Link Communication / Trainer System is ideal for pit-to-car communications and is also well-suited for karting. It was built with these two purposes in mind. You can talk back in the pits with a Bluetooth-connected smartphone and a noise-cancelling tiny amplifier. affixed with a Velcro patch to your suit or the side of your helmet; alternatively, it can be stored within your suit and worn around your neck on a lanyard. A USB C connector on the ZeroNoise Pit-Link Trainer Microphone Kit is used to link the micro amplifier to it.