MB Quart Formula 6.5-inch 3-way coaxial car speakers with aluminum dome tweeters and Butyl rubber surrounds.
 
Tweeters: Aluminum dome tweeters deliver great sound with increased reliability. 
Cone Material: Lightweight thermal-formed polypropylene cones enable faster midrange response
Surround/ Cone Coupling: Butyl rubber surrounds provide durability and deeper mid-bass impact. The cone/surround connection utilizes a high temp adhesive which assure the cone and surround do not separate in high power uses or extremes of weather.
Gasket: A textured ABS gasket assures a rigid linear seal to the mounting surface.
Voice Coil/Former Assemble: Pure Copper voice coil creates a strong magnetic field with a very thin extrusion. Kapton voice coil former is lightweight and efficiently dissipates heat.
Spider: Natural fiber allows flexibility while the infused epoxy gives strength during the manufacturing process.
Cooling System: Over-coil cooling system allows air exchange over the voice coil through the spider
Crossover: 6dB internal crossover integrated into the design to assure smooth midrange to tweeter frequency transitions. 
Frame: Heavy gauge progressive-die stamped steel frames for ultimate rigidity.
Motor: Ferrite magnt motor creates a strong magnetic field while remaining small enough to fit nearly every application. 
Connectors: Use spade connectors or solder direct for the best connection. Tinsel Leads: Highly conductive while remaining flexible during high power applications.