The HRMA-CF- 20-21 from HRmicrowave is a Band Pass Filter with Frequency 20 to 21 GHz, Insertion Loss 3 dB, Upper Rejection 60 dB, Lower Rejection 70 dB, Return Loss 20 dB. Tags: Module with Connectors, Combline Filter. More details for HRMA-CF- 20-21 can be seen below.