Plus One Woofer Cones: Plus One cones provide more overall speaker-cone area than other cones in its class giving them higher sensitivity, increased low-frequency output and more distinguished musical character. SSI (Switch-Selectable Impedance): New Stadium Marine 10" woofer features an exclusive dual impedance switch that lets you choose either 2- or 4-ohm load impedance option. SSI lets you reconfigure your system with the flip of a switch. Perimeter Illumination: Unique and eye-catching RGB illumination can display seven colors out of the box – or an almost unlimited number of colors when connected to an external lighting controller. One-piece Polymer basket: The polymer basket is durable over time even after prolonged exposure to sun, salt and moisture. Rubber surrounds are more reliable than foam and offer better edge protection. High Sensitivity: A high sensitivity rating combined with above-average continuous power handling makes it one of the loudest boat speakers available without sacrificing clarity, fullness and musical character. Harman Standard Reliability Testing: JBL speakers undergo a testing process that would destroy lesser speakers. JBL freezes them, bakes them, shakes them, blasts them with ultraviolet light and drives them at full power for days at a time.