The WLK9-50-65-40-6000-20 from Wainwright Instruments is a Low Pass RF Filter with Frequency DC to 50 / 65 MHz, Stopband Frequency Chosen Fco x 1.125 to 6 GHz, 3 dB Cutoff Frequency Choice of 50 to 65 MHz, Insertion Loss 1.15 to 1.85 dB, Rejection 40 dB. Tags: Module with Connector, Lumped Component Filter, Chebyshev Filter. More details for WLK9-50-65-40-6000-20 can be seen below.