YHD speaker 1: Different shape and watt 2: Well function on amplify the voice 3: Specially design for vehicle Features:1) Siren amplifers range from 40W, 80W, 100W, 150W to 200W2) Speakers range from 40W, 80W, 100W, 150W to 200W3) Customized tone4) with microphone YHD speaker