The 20825 3700-4200 5G from Microwave Filter Company is a Waveguide Filter with Frequency 3.7 to 4.2 GHz, Insertion Loss 1.24 to 1.4 dB, Operating Temperature -40 to 40 Degree C, Rejection 30 to 65.17 dB, Rejection Frequency 3.7 to 4.2 GHz. Tags: Band Stop. More details for 20825 3700-4200 5G can be seen below.