The FN-3819W from Filtronetics is a Low Pass RF Filter with Frequency DC to 250 kHz, Stopband Frequency 300 KHz to 10 MHz, 3 dB Cutoff Frequency 250 kHz, Insertion Loss 0.5 dB, Rejection 70 dB. Tags: Drop-In. More details for FN-3819W can be seen below.