Brand NEW! Including 90 Days USA Factory Warranty. The Dayton Audio Designer Series passive radiators are excellent general-purpose passives suitable for replacement or for new construction. Built to be a perfect match for the Designer Series drivers, these passive radiators feature the same steel frame, rubber surround, and anodized aluminum cone making them visually identical. Key Features ? Cosmetic frame edge looks great even when surface mounted ? Rear mounted screw allows easy mass adjustment for custom tuning ? Allows tuning small enclosures lower than using conventional ports ? Perfect match for Dayton Audio's aluminum cone Designer Series drivers. The Dayton Audio Designer Series passive radiators are excellent general-purpose passives suitable for replacement or for new construction. A built-in mass disc offers a good starting point for most designs, and a convenient M5 threaded hole (screw included) allows different types of weights to be added if desired. Cosmetically and mechanically, these passives match Dayton Audio's Designer Series drives, with a black anodized aluminum cone and medium-roll rubber surround for clean excursion and long life. The possibilities with these passives are endless, from desktop two ways to portable battery powered speaker systems. Specifications: ? Fs: 30.9 Hz ? Vas: 0.33 ft ? Qms: 3.48 ? Cms: 2.27 mm/N ? Rms: 0.7 kg/s ? Mms: 11.7 g ? Sd: 54.1 sq. cm. ? Xmax: 6 mm ? Dimensions: Overall diameter: 4.55", Cutout diameter: 3.69", Depth: 1.17". Note: Adding mass to the passive radiator will decrease Fs and increase Qms. Tip: As a general rule, the passive radiator(s) should have at least double the displacement of air (Vd) as the active woofer(s)/subwoofer(s) in the system. To calculate Vd: Sd x Xmax = Vd Product Specifications Nominal Diameter 4" Bolt Circle Diameter 4.21 Moving Mass Of Diaphragm (Mmd) 11.7 Thiele-Small Parameters Resonant Frequency (Fs) 30.9Hz Mechanical Q (Qms) 3.48 Compliance Equivalent Volume (Vas) 0.33ft Mechanical Compliance of Suspension (Cms) 2.27mm/N Maximum Linear Excursion (Xmax) 6mm Surface Area of Cone (Sd) 54.1cm Materials of Construction Cone Material Aluminum Surround Material Rubber Basket / Frame Material Steel Mounting Information Overall Outside Diameter 4.55" Baffle Cutout Diameter 3.69" Depth 1.17" # Mounting Holes 4 - All international buyers are responsible for all tax, duties and/or customs fees.