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 Series. 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). The TEAM-4 Series of Fi subwoofers is designed to meet the needs of the serious competitor and and monster basshead.