Free Air REVO subs are recommended primarily for Infinite Baffle (Free Air) applications where a dedicated subwoofer enclosure is not available or practical.The 8", 10”, & 12” REVO FA subs are available in White or Black frames (Black frames use metallic grey cones). REVO-8FA subwoofers are available in single 4 Ohm impedance.All REVO 8",10” & 12” Subwoofers share the same design features: Nylas Composite Frame - to withstand extreme environmental use. Designed to accept optional RGB wiring.Injection Molded Composite Cone – For durability & low distortion.Santoprene Rubber Spider – Much more durable to water & temperature changes than a traditional treated Cotton Spider used by the majority of marine speakers & subwoofers.Santoprene Rubber Surround – Offers a superior bond to the composite cone. Gold Plated Terminals –All REVO Subwoofers are sold without grills. 8 different grill designs are available separately for the 8" FA subwoofer.This will enable users to have matching grills on both REVO Coaxial In-Boat speakers & REVO Subwoofers.Optional RGB LED Kits are available to fit under all REVO 8",10” & 12” subwoofer grills to enable users to have thousands of LED light display combinations.