The TEAM 4 Series of Fi subwoofers is designed to meet the needs of the serious competitor and and monster basshead. With a massive 4″ voicecoil for increase thermal capacity, we designed the rest of the motor via FEA to optimize the proprietary US steel (water jet and machined in house at Fi when your order is placed). Using three ultra-high grade Y35 magnets, a flux flow derived back plate geometry, and a solid pole (with the optional cooling systems), there is plenty of thermal capacity in the TEAM v2 Series. Our Fi designed heavy 4 spider pack coupled with our special 144 tinsel count leadwire to keep the moving assembly under control at extreme excursion levels. The reworked surround geometry on the 12″, 15″, and 18″ models optimizes cone area vs excursion yielding the most output vs excursion. The 2018 TEAM 4 Series is designed for competition use and monster daily driving systems requiring high linearity and extreme power handling. From a punishing low end to the subtle nuances in your favorite reference track, the new TEAM 4 Series delivers!