Feature:1. HIGH QUALITY PLASTIC: This woofer diaphragm is made of high quality plastic material, which is durable.2. BASS DIAPHRAGM: Enhance the bass effect of the speaker and eliminate the disturbance of the airflow of the cabinet.3. FULL RANGE SPEAKER: This DIY subwoofer has a full range speaker bass enhancement effect.4. THE MAIN FUNCTION: The main function of this speaker diaphragm is the speaker, woofer, and bass vibration.5. PRODUCT SIZE: The product size is Approx. 92x92x22mm / 3.6x3.6x0.9in, the distance between adjacent screw holes is 61mm / 2.4in, and the distance between diagonal screw holes is 85mm / 3.4in.Specification:Item Type: Passive RadiatorMaterial: PlasticProduct Size: Approx. 92x92x22mm / 3.6x3.6x0.9inDistance Between Adjacent Screw Holes: Approx. 61mm / 2.4inDiagonal Screw Hole Distance: Approx. 85mm / 3.3in.Package List:2 x Passive Radiator8 x NailNote:Please allow 01mm / 00.04in error due to manual measurement. Thanks for your understanding.