The 21000 3625-4200 from Microwave Filter Company is a Waveguide Filter with Frequency 3.625 to 4.2 GHz, Insertion Loss 0.6 to 0.69 dB, Rejection 45 to 90 dB, Rejection Frequency 3.425 to 4.425 GHz. Tags: Band Pass. More details for 21000 3625-4200 can be seen below.