The WLK5-75-185-40-4000-20 from Wainwright Instruments is a Low Pass RF Filter with Frequency DC to 75 / 185 MHz, Stopband Frequency Chosen Fco x 1.35 to 4 GHz, 3 dB Cutoff Frequency Choice of 75 to 185 MHz, Insertion Loss 0.5 to 0.7 dB, Rejection 40 dB. Tags: Module with Connector, Lumped Component Filter, Chebyshev Filter. More details for WLK5-75-185-40-4000-20 can be seen below.