Polypropylene Cone - Neuron Series is equipped with Polypropylene Cone and is the preferred choice to withstand moisture and create a consistent playback Day or Night. Polypropylene has great characteristics that make it the ideal choice for vehicles. Silk Dome Tweeter - Neuron Component Speakers use a 1" silk dome tweeter to integrate with the midwoofer creating a harmonizing blend. Not overpowering the midwoofer and piercing to the ear at higher volumes. Silk Dome Tweeters is great for a wide genre of music. Heavy Gauged Stamped Steel Basket - Neuron performance speakers use a heavy gauged stamped steel basket coated in flat black to minimize vibrations. Vibrations on the speaker basket create distortion and making the basket thicker in gauge dramatically reduces the chances of occurring.