Polk Audio 4" Coaxial Speaker 135W Max

4" 2-way Speakers (Marine Certified)
Peak: 135 watts
RMS: 45 watts
Impedance: 4 ohms
Mounting Depth of 1.9" 
Dynamic Balance polymer/mica composite mineral filled cone is stiff yet lightweight for big sound and little distortion
19mm liquid-cooled silk/polymer composite dome tweeter with neodymium magnet for clear and detailed highs
Low-mass 2-Layer 25mm Kapton voice coil former is lightweight for high sound output
Multi-hole mounting pattern and shallow depth for easy drop-in installations in most cars
ABS Grilles, computer optimized and based on exclusive MOMO designs
Durable butyl rubber surround won't fall apart under the stress of extreme temperatures, sunlight or time
Pole Plate Heat Sink promotes better heat dissipation for superior power handling and reliability
Acoustically inert stamped steel basket
Flat Spider for faster, longer excursion linear motion
Flexible woven tinsel leads sewn directly into Spider for greater reliability
Frequency Response: 85-22,000 Hz