Features: brand new and high quality Small caliber, large power, large rubber edge, clean and firm bass, steady and powerful. Very suitable for the production of 2.1 speakers subwoofer unit and two-way Crossover speaker woofer. The cone is added with flax and bamboo fiber, the suspension is made of rubber and foam composite material, the real long-stroke, high-power design. The use of strong magnetic circuit system, air back flow system to ensure that the work in the high-power long stroke, bass clean, strong, fast. Low-frequency full of flexibility, used to upgrade the computer speaker subwoofer is also a good choice. Because of the high sensitivity, 25W-50W can easily push. Is a very rare bass unit. Specifications: Unit diameter: 4 inches Impedance: 4Ω. 8 Ω Rated power: 40W Maximum power: 50W Peak power: 100W Frequency response: 65Hz-3500Hz Sensitivity: 88dB Qts: 0.42 Box volume: 5.6L Maximum outside diameter: 116mm Diagonal screw hole: 105-108mm Speaker height: 65mm Speaker hole size: 93mm Cone Material: Cotton Paper + Hemp Size:as picture show Package Includes: 1PC x Subwoofer Speaker note: No retail package. Please allow 0-1cm error due to manual measurement. plz 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!