13TW5-3 TW5 13.5-inch Subwoofer Driver (600 W, 3 Ω) Groundbreaking large woofer performance is now available with only 2.5 inches of mounting depth. Our patented thin-line woofer technology compresses the architecture of the 13TW5 using a "concentric tube" structure that supports the oversized voice coil and the suspension attachments. This permits placing the large motor structure much further forward in the speaker than with conventional designs, while maintaining excellent linear excursion capability and mechanical stability. In keeping with its "tight-spaces" mission, the 13TW5 is also optimized for enclosures that are far smaller than most 12-inch woofers require and only a bit larger than the air space needs of a typical, small-box 10-inch woofer. We even designed the mounting system to allow it to fit in the same footprint as a typical 12-inch woofer. The 13TW5 is best used with amplifier power in the 250W - 600W range and is optimized to operate in a 0.80 cu. ft. (22.7 l) sealed enclosure.