The 20825 3680-4180 from Microwave Filter Company is a Waveguide Filter with Frequency 3.68 to 4.18 GHz, Insertion Loss 0.59 to 1 dB, Rejection 45 to 90 dB, Rejection Frequency 3.48 to 4.38 GHz. Tags: Band Pass. More details for 20825 3680-4180 can be seen below.