This tweeter is designed for general-purpose use in hi-fi, disco & PA speakers of all sizes. Piezo tweeters are capacitative therefore automatically reject low frequency power and are inherently high impedance. Therefore, these can be wired directly across a woofer without the need for a crossover. Because modern amps can produce very high frequencies (typically up to 100kHz) it is recommended to wire a 47Ω 3W resistor (Order Code: W47R) in series with each tweeter to limit damaging high frequency resonance. Available in two types: WF09K has a mounting flange flush with the front of horn for front fixing; WF55K has a mounting flange recessed 12mm from the front of horn for rear mounting.