Model  GZIW 250X Diameter  25 cm / 10" Mounting diameter  230 mm / 9" Mounting depth  130 mm / 5.1" Voice coil  50 mm Runddraht / 2" Round wire Cone  IMPP Power Handling  250 WRMS Impedance  4 Ohm SPL  86 dB Xmax  14 mm / 0.55" Fs  30.1 Hz Qts  0.44 Vas  43,8 L / 1.55 cu.ft. Sound Quality*  ☺ SPL Competition*  ☺ Low bass performance 20 - 50 Hz*  ☺ Mid bass performance 50 - 80 Hz*  ☺☺ Box recommendation vented   30 Liter / 1.06 cu.ft Rohr / Tube 1x Ø 8cm / 3.15" L= 14 cm / 5.51" Box recommendation sealed   20 Liter / 0.7 cu.ft & Free Air