Description:brand new and high quality Feature:Bass radiator, also known as passive speaker, is used to replace the inverted tube, the subwoofer made with the radiator and the traditional back subwoofer.Low frequency dive depth and backward , But the sense of speed is significantly faster than the back-type.Tight box advantage, Get rid of inverted pipe mouth to bring the wind noise.Allow you to mass tune the passive radiator to obtain the for ideal tuning frequency and additional without any additional amplifier power or enclosure volume.Dramatically increase subwoofer efficiency and capability for ultra low frequency reproduction at high decibel levels.Bass Vibrating Diaphragm only, other accessories demo in the picture is not included Specifications:Item Type: Bass Vibrating DiaphragmMaterial: RubberSize: 75mm/2.9in, 90mm/3.5in, 92mm/3.6in, 95mm/4in,139mm/5.4in(Optional)Color: BlackQuantity: 2 PCS Note:No retail package.Transition: 1cm=10mm=0.39inchPlease allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you Package Includes:2 x Bass Vibrating Diaphragm