The SiMS18R75/4R5-8D1 from Sainty-Tech Communications Limited is a Band Pass Filter with Frequency 16.5 to 21 GHz, Center Frequency 18.75 GHz, Insertion Loss 1.5 dB, Rejection 30 dB @14.6GHz&22.8GHz, 40 dB @13.5GHz&24GHz, 60 dB @DC~10GHz, 40 dB @25~35GHz, Upper Rejection 30 to 40 dB. Tags: Surface Mount, Cavity Filter. More details for SiMS18R75/4R5-8D1 can be seen below.