Klipsch Palladium High Frequency Replacement Tweeter works in the following models P-39F, P-38F, P-37F, P-17B, P-27C This was removed from a Pallidum P-39F Floor Standing Speakers. it is in good working order. Please see pics for cosmic condition. Description from owners manual: Treble Compression Driver Low distortion, high sensitivity, wide bandwidth and neutral tonality have been, in this ground-breaking design, pushed beyond the standards for any previous Klipsch driver. Built around a .75-inch titanium dome, the tweeter makes use of two very large high temperature N35H neodymium magnets in an unconventional configuration. The titanium dome and surround are formed as one common unit. The chamber behind the tweeter dome is resistively damped via a filled tube to reduce reflection of the back wave—and thereby the distortion that would otherwise be produced. The phase plug that puts the dome into a compression mode also has a unique chamber within it that extends the upper frequency limit of the driver. This proprietary technique offers numerous benefits, including the elimination of undesirable standing waves in the high pressure layer between the phase plug and horn. The result is a smooth impedance transfer function, and a benign load on the partnering amplifier. Additionally, this technique produces smoother amplitude response through the high frequency range. With its unique horn and phase plug, the P-39F tweeter demands far less drive current from the amplifier, so the driver can maintain full dynamic capability at any volume level. This driver is inherently flat from 3 KHz to 30 KHz. and has an inherent sensitivity some 10 dB greater than direct radiating designs. Distortion is also reduced by a factor of 10 dB, against conventional tweeters