Products specification Model no.: SD-21006A Size:21" Rated Power: 1200W Peak Power:2400W Impedance:8 Ohm DC Impedance: 5.4 Ohm Sensitivity:97dB Frequency Response:28hz-2khz Voice Coil Diameter: 4 Inch Voice Coil Wire Material: Copper Bobbin Material: Fiber Glass Voice Coil Layers: inside and outside each 1 layer Dampers: one Cone: Paper Magnet Size:123 OZ Mounting Detail: Outer diameter:544mm/21" Hole Cut Out diameter:504mm/19.84" Depth:238mm/9.37" Packing Information: 1pc one carton,Website:://.soundsingpro.com, brown inner and outer box Carton Size: 58*58*31CM Other Information Place of Original: Guangzhou, China Payment Terms: T/T, Western Union, Money Gram Port of Delivery: Huangpu, Guangzhou, China Production Lead Time:30days after receive 30% T/T