The FN-3119W from Filtronetics is a Low Pass RF Filter with Frequency DC to 2 kHz, Stopband Frequency 3 to 3.8 KHz, 3 dB Cutoff Frequency 2 kHz, Insertion Loss 0.5 dB, Rejection 20 to 60 dB. Tags: Module with Connector. More details for FN-3119W can be seen below.