SSL crossovers allow you to direct specific frequency ranges to the Sound Storm tweeters, full range speakers, and subwoofers designed to best reproduce those frequencies: Essentially, they tell your tweeters when to tweet and your woofers when to woof! The SX210 is a 2-way electronic crossover with remote subwoofer level control. It features front, rear, and subwoofer inputs as well as independent front, rear, and subwoofer output levels and level controls. Signal-to-noise ratio is >100dB. Other standard features include a phase inversion switch (sub out), stereo/mono switch (sub out), and Bass Boost (0 to 12 dB) @ 45Hz. Crossover frequencies can be selected as follows, high pass from 50Hz to 1.5kHz, and subwoofer from 35Hz to 400Hz. For technical questions about this product please visit our website, soundstormlab.com, or call a technician at 888.38.STORM. When it comes to building an impressive and affordable home-quality theater in your vehicle, Sound Storm is your solution. Let us prove to you that everything else is just noise.