Massive Audio GTX 104 / 10" Dual 4-Ohm Voice Coil 1400W Car Stereo Subwoofer

It was installed in a single fully-sealed enclosure, and used in my personal car with a Pioneer 1000D amp driving it, at about 3/4 power for roughly 30K miles worth of normal driving. It's never been abused or used for competition.

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