This kind of speaker is with intensity,waterproof,dampproof and corrosionproof shape , durable and energy saving also it is adopted quality alnico,and it is provide with high efficiency conversion, high- pitched advamce technics ,nicer making,high dependability.also can provide all kinds of speaker windings and fittings. speaker series are ftted for same power sirens.horn series can be directly used conneting electronic source,and with some tones.