The 15RBX100 high output subwoofer features a 25mm high, 4” (100mm) diameter copper wire voice coil that is combined with a laminated double silicone spider, water resistant curvilinear cone, and triple roll surround — for even more excursion and linearity. The corrosion resistant motor structure incorporates an aluminum demodulation ring that effectively controls inductive rise as well as harmonic and intermodulation distortion. This subwoofer can be used for a wide variety of applications, including compact vented enclosures as small as 80 Litres.