6 1/2" Polypropylene (400-1011A) Features Faxback Doc. # 14029 Woofer Light, Rigid, Polypropylene Cone - provides superior uniformity, reduced distortion, and a smooth response. Rolled Urethane Foam Surround - minimizes distortion and improves clarity. Long-Excursion Voice Coil - delivers clean, solid sound. (ALL-03/09/95)