For all high power bass applications. The Sigma Pro 18 has a 4" polyamide-imide coated two-layer 28 ga. copper voice coil, kapton coil former, 109 oz. ferrite magnet, vented and extended core, paper cone with cloth edge, and a paper dust cap.

MPN: SIGMA PRO-18A

Specifications
Nominal Basket Diameter 18" / 457.2mm
Impedance 8 ohms
RMS Power Rating 1300 Watts
Frequency Response 25Hz - 2.5kHz
Sensitivity (1W/1m) 100dB
Voice Coil Diameter 3" / 76.2mm
Max. Crossover Frequency 2.5kHz

Mounting Information
Overall Diameter 18" / 457.2mm
Bolt Circle Diameter 17.25" / 438.2mm
Baffle Cutout Diameter 16.625" / 422.3mm
No. Of Mounting Holes 8
Mounting Hole Diameter 0.275" / 7mm
Overall Depth 8.15" / 207mm
Magnet Weight 120 oz.
Shipping Weight 27.2 lbs. / 12.4kg.