The BSF-1765MS1 from RF ONE Electronics is a Band Stop Filter with Stopband Frequency 1.75 to 1.78 GHz, Insertion Loss 3 dB, Rejection 40 dB, Power 40 W, Return Loss 10 dB. Tags: Module with Connectors, Cavity Filter, Ceramic Filter, LC Filter. More details for BSF-1765MS1 can be seen below.