Features: A low frequency passive radiator membrane vibrating plate for DIY speakers to enhance the effect. Made of premium materials which ensure maximum strength and durability for long-lasting use. Newly improved radiator, allows you to mass tune passive radiator for the for ideal tuning frequency and for extra . Outstanding tone, better enjoy, bring you a strong . Suitable for use in a closed cabinet to enhance the , widely used for speaker, woofer, loudspeaker, vibrating. Specifications: Material: Metal+Rubber Color: Black Diameter Unit of Measure: Approx. 160 mm/6.29 inch Thickness: Approx. 10 mm/ 0.39 inch, 65 Degrees Mounting Hole: Approx. 144.5 mm/5.68 inch Inner Diameter: Approx. 98 mm/3.85 inch Package Includes: 1 Pair 6.5-inch 160mm DIY Bass Speaker Vibration Membrane note: Bass diaphragm only, other accessories demo in the picture are not included! Please allow 1-2cm errors due to manual measurement,pls make sure that you do not mind before you mind. Due to the difference between different monitors, the picture may not reflect the actual color of the item.