The SiMS20R4/5R2-8D1 from Sainty-Tech Communications Limited is a Band Pass Filter with Frequency 17.8 to 23 GHz, Center Frequency 20.4 GHz, Insertion Loss 2.5 dB, Rejection 30 dB @16.2GHz&24.5GHz, 40 dB @15GHz&27GHz, 55 dB @DC~13.2GHz, 45 dB @28~40GHz, Upper Rejection 30 to 45 dB. Tags: Surface Mount, Cavity Filter. More details for SiMS20R4/5R2-8D1 can be seen below.