The BOSE's MB12WR is a modular bass passive speaker designed to offer bass augmentation for Bose LT arrays and other subwoofer applications. It comes in black and is weather resistant. A single 12" high-excursion woofer with a 4" voice-coil and a power handling of 400W RMS is housed in the Baltic birch enclosure (1600W peak). The subwoofer has a frequency response of 40 to 280 Hz and a front-loaded transmission line design that reduces port turbulence distortion by providing a peak-free extended low-frequency.