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. The low frequency dive depth is equivalent to the reverse type. The sense of speed is obviously faster than that of the reverse type, which has the advantage of a certain closed box. Completely eliminates the drawback of the inverted structure - that is, the wind noise brought by the inverted nozzle. Make great effect on enhancing the bass, bass booster, convenient debugging. Increase the lower potential of the bass, the sound more excellent. Dramatically increase subwoofer efficiency and capability for ultra-low frequency reproduction at high decibel levels. New and high quality. Material: Rubber. Type: sound film, diaphragm. Model: 57-a1.0-65 °. Number of channels: auxiliary bass. Size: 57*1mm. Specification of iron sheet: 34*1mm. Color: as shown in the figure. Package includes: 1pc. Note: Due to the different monitor and light effect, the actual color of the item might be slightly different from the color showed on the pictures. Thank you! Please allow 1-2mm measuring deviation due to manual measurement.