The BSF-912MS1 from RF ONE Electronics is a Band Stop Filter with Stopband Frequency 0.864 to 0.96 GHz, Insertion Loss 3.5 dB, Rejection 40 dB, Power 40 W, Return Loss 5 dB. Tags: Module with Connectors, Cavity Filter, Ceramic Filter, LC Filter. More details for BSF-912MS1 can be seen below.