The polypropylene woofer with its durable hi-roll rubber surround ensures that you will enjoy powerful sound every time you drive. The oversized cone moves more air than other speakers of the same or similar size, that extra punch you want from the speaker's performance. A 1/2" textile dome tweeter for smoother and clearer highs and you'll have a sound that is definitively Infinity. These speakers will hit new levels when powered by an external amplifier, but they are also sensitive enough to be a good match-up for aftermarket or factory stereo. These 3-ohm speakers combined with the speaker wire in your car, so your car stereo sees 4-ohm impedance, making it a safe way to get a little more power out of your system.