The 123FPM is a high efficiency, (98 dB 1watt / 1 meter) 12-inch mid bass woofer with incredibly linear frequency response characteristics. The 123FPM uses a lightweight rib-reinforced cone assembly along with a precision double roll constant geometry surround. This combination provides remarkable strength, high efficiency and a excursion linearity of 10.2mm.Magnetic CircuitREDCATT engineers have developed a lightweight, inside-neodymium slug based magnetic circuit capable of delivering the highest level of performance providing a consistent, high integrity magnetic flux gap, ultra low distortion characteristic and high efficiency cooling system. The magnetic circuit design is optimized to generate the minimum amount of flux modulation, providing exceptional stability.