Ground Zero GZRW 300SPL Pink subwoofer 12" (300 mm).

Ground Zero GZRW 300SPL Pink subwoofer 12" (RMS 1000 W, 2+2 Ohm, 300 mm).

Cast frame, High-roll sandwich surround and heavy magnet are the first thing you notice about this subwoofer. When you look closer, you can see other details that help making this driver so excellent performer. 
Reinforced paper cone with extremely tough dust cap is double stitched to surround. voice coil cooling happens through the big tunnel in pole piece and with cooling vents in the frame. 
Voice coil is 3″ in diameter and is wounded of OFC wire. Push type terminals hold tight the cables and conductors wowen to Polycot spider can handle high X-max. 
You can not see all the things that matter and most important of the invisible ones is Klippel-optimization. With Klippel device it is possible to monitor all parts of the subwoofer during over 10 hour torture test. 
During the test power handling capability of woofer is really tested by feeding even 4 times more than driver is built to handle. Meaning of this torture is to find out the weakest links in prototypes and make them stronger for final product.