The FN-3749W from Filtronetics is a Low Pass RF Filter with Frequency DC to 1680 MHz, Stopband Frequency 2560 MHz, 3 dB Cutoff Frequency 1680 MHz, Insertion Loss 0.5 dB, Rejection 40 dB. Tags: Module with Connector, Surface Mount. More details for FN-3749W can be seen below.