Polk Audio DB571 360 Watts 5" x 7" Coaxial Car/Marine Loudspeaker (2 pairs) 5x7 Dynamic Balance polymer/mica composite mineral filled cone is stiff yet lightweight for big sound, little distortion. Low-mass 2-layer 25mm Kapton voice coil former is lightweight for high sound output. Kapton's high melting temperature (725F/400C!) ensures high power handling and kick-butt reliability. Stainless steel mounting hardware