JBL's slot-port enclosure is engineered and "tuned" to the optimal frequency by the JBL engineering team. The enclosure material is MDF (medium-density fiberboard) to minimize resonances and unwanted ring. Lightweight but stiff polypropylene woofer cone provides clean reproduction and superior durability in an easy listening or high volume venue. The JBL subwoofer system's built-in amplifier provides electronics matched and optimized for woofer characteristics and enclosure acoustics.
Class D operation also means the amplifier runs cooler and draws less current from the vehicle's electrical system. The oversized protection bars project a "serious car audio enthusiast" statement, but more importantly they do an excellent job of protecting the speaker from accidental damage. JBL speakers have to undergo a testing process that would destroy lesser speakers. JBL freezes them, bakes them, shakes them, blasts them with ultraviolet light and drives them at full power for days at a time.
Car Audio 8-inch Loaded Subwoofer in Slot Ported Box with Built In Amplifier. JBL BassPro 8 Slot-Port Enclosure. Frequency Response: 30Hz - 200Hz. Maximum Current Draw: 9.5A. What's In The Box. 1 x Powered Subwoofer Enclosure.1 x Quick Start Guide. 1 x Wire Harness with Connectors. 2 x two-color JBL Brand Stickers. Also if you are in AK, HI, PR, GU, SAIPAN OR U.