The BSF-778MS1B from RF ONE Electronics is a Band Stop Filter with Stopband Frequency 0.773 to 0.783 GHz, Insertion Loss 1 dB, Rejection 60 dB, Power 40 W, Return Loss 10 dB. Tags: Module with Connectors, Cavity Filter, Ceramic Filter, LC Filter. More details for BSF-778MS1B can be seen below.