ParameterModel No :18100General SpecificationsNominal diameter? 460 mm/18 inPower rating? 1000W(AES)Nominal impedance? 8OHMSensitivity? 97 d BFrequency range 40-1000 HzChassis type? cast aluminumMagnet type? FerriteMagnet? weight? 125 ozVoice coil diameter? 99.2 mm/4 inchCoil material? copperFormer material? Glass fiberCone material? PaperSurround material? ClothSuspension? Double?Kind of layers? outside/insideNumber of layers 2Gap depth? 14.0 mm/0.55 inVoice coil winding width? 23 mm/0.9inNet weight? 14? kgShipping weight 14.5 kgFeaturesThe 18 inch Stage speaker? anchors our ferrite subwoofer line, and features an all new FEA optimized motor structure. The 25mm high, 4" (99.2mm) diameter fibreglass inside-outside copper voice coil is combined with a laminated double silicone spider, water resistant curvilinear cone and triple roll surround, for even more excursion and linearity. http://www.chinasoundspeaker.co...ch-1000w-pa-speaker.html