Soundking researched the good line array woofer, the size have 8"" woofer,12"" woofer,15"" woofer and 18"" woofer, this woofer have big power.
> Compact, High power, high sound pressure;
> 2 x 18" long throw speaker units, 4" voice coil endure high temperature;
> Direct-radiating phase inverted enclosure;
> Reinforced bar reduces resonance;
> Large phase inverted tube reduces airlow sound;
> Match with the full-range speaker as a powerful PA sound-reinforcement system.