4”/100mm Coaxial Speakers Flush profile tweeters and a compact basket design for easy installation. High quality polypropylene cone material for great sounding audio. Quality butyl rubber surround for excellent durability and prolonged performance. Ferrofluid tweeters enable enhanced thermal contact for increased reliability and optimum damping for the voice coils. Specifications Peak Power: 120 Watts  Rated Power: 30 Watts  Frequency Response: 99Hz-20KHz  Impedance: 4 Ohm  Sensitivity: 86dB  Cone Material: Polypropylene  Tweeter: PEI  Mounting Depth: 43mm (1-11/16”)  Mounting Diameter: 103 mm (4-1/16”)