Sensitivity: 93.7 dB - Usable Freq. Range: 25 Hz ~ 1 kHz * Cone: Kevlar(r) impregnated cellulose * Voice Coil Diameter: 4.0"/ 100 mm - Voice Coil Material: Polyimide coated copper ribbon wire Polyimide-impregnated fiberglass former Nomex(r) stiffener Solderless diffusion welded OFHC copper leads * Voice Coil Diameter: 4.0"/ 100 mm - Voice Coil Material: Polyimide coated copper ribbon wire * Polyimide-impregnated fiberglass former Nomex(r) stiffener Solderless diffusion welded OFHC copper leads