Designed using the bass-enhancing technology found their W7 subwoofers, the speaker is mounted using JL Audio's patented aluminum cast "Elevated Frame" cooling system. This provides maximum airflow accross the top-plate directly onto the voice coil windings, giving a good low frequency response and dynamic range. The polypropelene cone and butyl suspension elements were designed and manufactured by the world-famous Dr. Kurt Müller & Co of Germany. The kit also comes with ABS spacer rings to be placed between the speaker and mounting surface if rear clearance is an issue. The 1" (25mm) light-weight aluminum dome tweeter is suspended with synthetic rubber to dampen ringing and features a Nomex voice coil to further reduce its mass. The tweeters come mounted in enhanced flush mount fixtures, but can be mounted using a compact flush mount or angled surface mount. The 2-way crossover features a high pass filter with 5 (+1.5dB, Reference, -1.5dB, -3.0dB and -4.5dB) levels options and a low pass with 4 levels, ranging from "low" to "high".