The Telewave TWPC-0405-1 is a 5 in diameter, 1/4 wavelength, high "Q" bandpass cavity filters with superior selectivity. Bandpass cavities reject all frequencies outside a narrow passband. These cavities reduce transmitter sideband noise, and also protect receivers against desensitization. The TWPC-0405-1 covers 40 – 50 MHz. The tuning range of these cavities is approximately +/- 2.5 MHz from center frequency as built. The cavity has to be tuned to a specified frequency prior to shipping.