DD Audio DVC DD-818-D2 Power Range: 1000-2000 RMS, 6000 Peak Voice coil diameter: 4″, USA made, aluminum wire on aluminum former. Motor size: triple stack magnet, CnC 15mm top plate, double vented, outer shorting ring. Excursion: 75mm Spiders: Built-in double lead wire, progressive roll, 5 layers. Cone/surround: Nonpressed synthetic pulp, EROM surround with red stitching. Net weight: 52 pounds, 23.7 kilos The 800 series woofers features: Double Stitched EROM Surrounds High-temp 4.0″ all aluminum voice coils 1000w-2000w RMS, 6000w Peak 9 layer laminated spiders Non-pressed paper cones Cast aluminum basket with cooling vents 10-AWG Direct Connect Leads Back plate coil gap venting 3-Way cooling Extended pole piece 325oz triple stack magnet The 800 series will be offered in 12″, 15″, and 18″ basket sizes with your choice of dual 1 ohm or dual 2 ohm voice coils. Specifications Continuous Power Range: 1000-2000 watts Burst Power: 6000 watts Impedance Options: D1.0 Ohm/ D2.0 Ohm Suspension Type: Triple stack 9 layer composite Woofer Diameter: 18″ Coil Diameter: 4″ Magnet Weight: 325 oz *SPL: 91.34 dB @ 1w/1m Fs: 34.32 Hz QTS: .517 Qes: .574 Qms: 5.197 VAS: 4.41 cubic feet **Xmax: 18 mm 2-Way Suspension Travel: 80mm Displacement: .27 cubic feet Frame OD w/ gasket: 18.5625″ A – Frame OD w/o gasket: 18.25″ B – Cutout Diameter: 16.6875″ C – Mounting Depth: 10.25″ D – Motor Diameter: 9.5″ E – Motor Height: 3.75″ F – Surround Height: 1.25″ Shipping Weight: 59.1 lbs