BMW woofers Suitable to ALL BMW models with underseat woofer locations. Fs 68.5 Hz Qts 0.97 Vas 17.3 liters B/L 4.8 SPL 88 dB impedance 2 ohms 2″ copper voice coil Power handling 100W RMS / 180W MAX Neodymium magnet Coated paper cone Nomex spider.