The SoundQubed HDX4.2-18D1 is a competition-grade 18” subwoofer engineered for massive output, deep frequency extension, and hardcore durability. Delivering an earth-shaking 4000W RMS and 16,000W burst power, this dual 1-ohm sub is built to dominate high-output systems with force and precision. With a sensitivity of 90.4dB and a resonant frequency of 31.6Hz, it delivers powerful, accurate bass capable of shaking any vehicle to its core. Featuring a massive 402 oz magnet, oversized 4” high-temp voice coil, and a 23mm Xmax, the HDX4.2-18D1 offers extreme excursion and superior thermal handling. Perfect for ported enclosures between 5 to 7 cubic feet, the HDX4.2-18D1 is the go-to sub for serious competitors and bassheads who demand unmatched performance and reliability.