The RSF-1900.000-40000-1109-TR-NS2 from Raltron is a Band Pass Filter with Frequency 1.88 to 1.92 GHz, Bandwidth 40 MHz, Center Frequency 1900 MHz, Insertion Loss 2.8 to 3.3 dB, Rejection 70 to 8 dB. Tags: Surface Mount, RF SAW Filter. More details for RSF-1900.000-40000-1109-TR-NS2 can be seen below.