15″ SPL Competition subwoofer Diameter 38 cm / 15″ Mounting diameter 391 mm Mounting depth 307 mm Voice coil 4″ Flat wire Cone Carbon composite fiber Power Handling 20000 W SPL Power Impedance 2 x 1 Ohm SPL 91.42 dB Xmax 30 mm ( one direction ) Fs 41.2 Hz Qts 0.19 Vas 25.6 L Suitable for: Sound Quality use ☺☺ SPL Competition use ☺☺☺☺☺☺ Low bass performance 20 – 50 Hz use ☺☺.