The BSF-5220MS1 from RF ONE Electronics is a Band Stop Filter with Stopband Frequency 5.17 to 5.27 GHz, Insertion Loss 2.2 dB, Rejection 50 dB, Power 20 W, Return Loss 10 dB. Tags: Module with Connectors, Cavity Filter, Ceramic Filter, LC Filter. More details for BSF-5220MS1 can be seen below.