GHXAMP 400W 3 Way Crossover Hifi Tweeter Midange Woofer Speaker Crossover 1250H/5000HZ With High-pitched Protection 1PC1. Circuit: The treble, midrange and bass are all designed with a second order standard 12db oct circuit. 2. High tone band current limiting over current protection bubble: When the current is small, the bubble acts as a wire; when the current is too large, it acts as a load, consumes the current, and the high pitched sound is not burned by the current too much. It belongs to a movable type protection. 3. The inductor is wound with oxygen free copper