The Skar Audio Ddx-15 D4 Is A Competition Grade 15-Inch Dual 4-Ohm Car Subwoofer The Ddx Line-Up Was Engineered By Skar Audio To Be An Spl Grade Woofer That Could Also Be Utilized In Daily System Applications Allowing Non-Competitors To Use The Same Subwoofers As Those Competing In The Lanes Every Component Used In The Design Of These Woofers Is Of The Highest Quality For Reliability And Increased Performance Conservatively Rated At A 1500 Watts Peak Power And 1000 Watts Rms Power This Subwoofer Was Engineered To Be Extremely Loud Featuring A Massive Double Stack Motor (202 Oz) 25 Pure Copper High Temperature Voice Coil And A Competition Grade Pressed Paper Cone Stitched To The High Roll Foam Surround The Woofer Comes Equipped Ready To Handle Serious Amounts Power Dual 4-Ohm Voice Coil Configuration Specifications - Peak Power 1500 Watts Rms Power 1000 Watts Sensitivity (Spl) 900 Db Frequency Response 30 - 400 Hz Fs 416 Hz Qts 045 Qms 43 Qes 050 Bl 323 N/A Vas 477 L Subwoofer Mounting Depth 783 Subwoofer Cut-Out Diameter 1397