The new subwoofer incorporates the One Systems 18I/O 18-inch extended bass transducer with patented Inside/Only (I/O) voice coil design. Coverage is nearly 100 percent omnidirectional, and frequency response (+3 dB) is stated as 40 Hz – 120 Hz. The medium-density polyethylene enclosure is optimized for high UV exposure and harsh environments, measuring 23 x 20.1 x 20.7 inches.

All external rigging and suspension hardware, as well as the metal grille, are built using 304-grade stainless steel. The structural internal rigging is made with high-strength aluminum. The grille is a 3-layer “rain shield” design minimizes direct rain contact with the system’s transducers. The unique vent design also allows for easy moisture drainage from the interior of the enclosure.

The 118IM-Sub is designed to IEC 529 IP45 (solid object penetration to 1 mm (0.04 inches) and water jets from any direction). The enclosure and components are also designed to Mil Spec 810.