BB Distribution - The 4 Focal Flax subwoofers consist of straightforward 4-Ohm voice coils which are perfectly suited for small enclosures (closed or bass-reflex) as small as 0.35 CuFt. The Flax subwoofers
Flax Universal 8" Subwoofer Enclosure with P20F Subwoofer
Focal Performance Sub P 20F Expert Series 8" 4-ohm component subwoofer at Crutchfield
Focal (Car) P20F - In-Car Subwoofer Chassis im Test - sehr gut - hifitest.de