Perfect Car HiFi Subwoofers for Free Air Applications Coated paper cone with reinforced rings and long excursion surround of special design. The magnetic systems were improved yet again and now provide an even higher drive power, the approved far protruding lower pole plate ensures an exceptionally high excursion accordingly. Car HiFi power bass speaker, 350WMAX, 4Ω 25cm (10") bass speaker with coated cone as an efficient bass addition for free air applications in compact vehicles. New improved design with protruding lower pole plate for an even longer excursion. With the new drive parameters which show a clearly improved Q factor (Qts), these speakers can now be recommended for closed cabinets and even bass-reflex cabinets with large dimensions, too!