In the 22nd century, a Starfleet earpiece was usually a white, round module with a blue center, adjacent to six oblong holes. The user of the earpiece would press it against their right or left ear, enabling them to hear the device. This style of earpiece was commonly used by Communications Officer Hoshi Sato aboard the NX-class starship Enterprise. (ENT: "Broken Bow", et al.) Earpieces were used by officers on the bridge of the USS Kelvin, which doubled as communicators. A variant lacking the communicator end was worn by the ship's tactical officer. (Star Trek)