The RSF-1900.000-40000-1109-TR-NS1 from Raltron is a Band Pass Filter with Frequency 1.88 to 1.92 GHz, Bandwidth 40 MHz, Center Frequency 1900 MHz, Insertion Loss 1.8 to 2.1 dB, Rejection 50 to 25 dB. Tags: Surface Mount, RF SAW Filter. More details for RSF-1900.000-40000-1109-TR-NS1 can be seen below.