The Reefs Standard 25T Round Horn is a steering component used in radio-controlled vehicles. It connects to a servo motor and transfers the motor's rotational movement into linear movement to steer the vehicle. The 25T refers to the number of splines on the horn, which are used to attach the horn to the servo output shaft. The round shape of the horn allows for smooth and consistent movement, making it a popular choice for RC enthusiasts. The Reefs Standard 25T Round Horn is made from durable materials and is designed to withstand the demands of high-performance RC vehicles.