Scan-Speak Classic 18W/8545K00 18cm Midwoofer 8ohm, Carbonfiber Paper Cone, Fiberglass VC Former The Symmetric Drive (SD-1) concept with copper in the magnet system was invented by Scan-Speak. High-quality magnet system design has thus been a key feature of Scan-Speak design since the companys inception. The Classic woofers are highly praised, and are used in some of the worlds most exceptional high-end Loudspeakers. Some feature Kevlar cones others have the innovative Carbon fibre paper cones. - Patented Symmetrical Drive Motor Design - Low-Loss linear suspension - Air Dried Paper/Carbon Fibre Cone - Low Damping SBR Rubber Surround - 42mm Voice Coil w. fiber glass foil