DC GOLD AUDIO woofers are designed to be used in pairs. Their extra-long 1.5" voice coils allow each woofer to move 3/4" peak to peak. With a combined area of close to a 15" woofer; you will really "rock your boat". Available in both Classic and Reference line you will enjoy the bass extension that has been lacking and a smooth enough mid-range to blend with your top end no matter where you cross-over.