Powerbass 10' L-Series Subwoofer (L-1004D): Car Electronics. Buy Powerbass 10" L-Series Subwoofer (L-1004D): Everything Else - ✓ FREE DELIVERY possible on eligible purchases. Injection molded PP cone . Large roll, nbr rubber surrounds . One Piece Plated Backplate and Extended Pole Piece . Large Motor Structures for High Power Handling . Dual 4-Ohm voice coils/ 2.5-inch vented ksv voice coil former . Our new L Series subwoofers have been engineered to deliver the earth-shaking SPL and smooth bass that sq. purists require. Each L L-1004D features a redesigned injection molded PP cone. This cone combines deep bass and distortion free sound. Next we designed a single piece CNC machined back plate with extended pole piece to insure a strong symmetric Magnetic field for increased operating efficiency. A sandblast finish was applied for good looks and durability. To make the bass super tight, our engineers designed large roll nbr (nitrile) rubber surrounds which allows free movement of the cone for maximum SPL, a large motor structure for high power handling.5” Black kapton voice coil former for optimum performance and cooling for maximum heat dissipation. . . .