The 20825 3660-4200 from Microwave Filter Company is a Waveguide Filter with Frequency 3.66 to 4.2 GHz, Insertion Loss 0.72 to 1 dB, Rejection 45 to 90 dB, Rejection Frequency 0.342 to 4.425 GHz. Tags: Band Pass. More details for 20825 3660-4200 can be seen below.