The Hertz SPL Show car audio subwoofers are the ideal solution for building mobile audio systems with emphasis placed on low frequency power and impact. Featuring a stacked double magnet motor assembly and 2 + 2 Ohm dual voice coil, the three models, SX 250D, SX 300D, SX 380D differ only in their cone diameter: 250 mm, 300 mm, 380 mm respectively. The SPL Show moving assembly is designed to ensure long and linear excursion. They feature a dual spider design and an aluminium voice coil wound on a four-layer former. The back vented spider support decreases the voice coil operating temperature, even during enhanced SPL usage.