Compound horns‎,‎ powerful and crisp voice‎,‎ fan‎-shaped sound transmission‎,‎ and battery saving‎.‎ Use imported manganese steel sound board‎,‎ which can keep clear and powerful sound at all times in different environments‎.‎ It gives a strong sound with smaller and lighter design‎.‎ Unique waterproof buckler design to get best waterproof performance‎.‎ Excellent original equipment standards‎,‎ working on temperature range of ‎-40 degrees to +80 degrees‎,‎ and can whistle for three minutes‎.‎ High quality material can prevent salt‎,‎ resist the hit of sand and stone fragments‎.‎ Be able to adapt to all kinds of weather‎.‎