Eminence DELTA PRO-18C 18″ 500 Watt Pro Audio Woofer – 4 ohms Midwest Speaker is an authorized Eminence Distributor and we supply the vast majority of the Eminence product line. Please contact us if you want a different model. New in Box. Price is for (1) one speaker. Just change the quantity to order more. Long throw subwoofer for very small vented boxes. Over-sized top plate and large pole vent assist keep the coil cool. SpecificationNominal Basket Diameter18″, 457 mm –> Nominal Basket Diameter18″, 457 mmNominal Impedance*4 ΩPower Rating**Watts500 WMusic Program1000 WResonance27 HzUsable Frequency Range35 Hz – 0.2 kHzSensitivity***94.4 dBMagnet Weight67 oz.Gap Height0.38″, 9.7 mmVoice Coil Diameter2.5″, 64 mm Thiele & Small ParametersResonant Frequency (fs)27 HzDC Resistance (Re)3.8 ΩCoil Inductance (Le)2.65m HMechanical Q (Qms)13.24Electromagnetic Q (Qes)0.32Total Q (Qts)0.32Compliance Similar Volume (Vas)488.8 liters / 17.26 cu.ft.Peak Diaphragm Displacement Volume (Vd)796 ccMechanical Compliance of Suspension (Cms)0.25 mm/NBL Product (BL)16.5 T-MDiaphragm Mass Inc. Airload (MMs)137 gramsEfficiency Bandwidth Product (EBP)84Maximum Linear Excursion (Xmax)6.7 mmSurface Area of Cone (Sd)1188 cm2Maximum Mechanical Limit (Xlim)15.0 mm Mounting InformationRecommended Enclosure VolumeSealed N/a Vented 85.00-283.00 liters / 3.00-10.00 cu.ft. Driver Volume Displaced0.212 cu.ft. / 6.01 litersOverall Diameter18″, 457.2 mmBaffle Hole Diameter16.57″, 420.9 mmFront Sealing GasketYesRear Sealing GasketYesMounting Holes Diameter0.28″, 7.1mmMounting Holes B.C.D.17.25″, 438.2mmDepth8.13″, 206.5 mmNet Weight17 lbs, 7.71 kgShipping Weight20.5 lbs, 9.3 kgs Materials of ConstructionCoil ConstructionCopper voice coilCoil FormerPolyimide formerMagnet CompositionFerrite magnetCore DetailsVented and extended core Basket MaterialsDie-cast aluminum basketCone CompositionPaper coneCone Edge CompositionCloth cone edgeDust Cap CompositionSolid composition paper dust cap For more specs talk over with: http://www.eminence.com/pdf/Delta_Pro_18C.pdf MADE IN THE USA. FAST FREE UPS GROUND SHIPPING TO THE LOWER 48 UNITED STATES ONLY. Does not include Alaska, Hawaii, and Puerto Rico. INTERNATIONAL SHIPPING TO CANADA WELCOME!!! Our shipping costs don’t include your country’s customs charges, taxes and other fees. Please do NOT ask us to send as a gift or to lower the declared value at the customs forms. *Returns only accepted if speaker has NOT been mounted or soldered. Shipping costs aren’t refundable and buyer will have to pay for return shipping.