The WLJ9-45-50-40-3000-100 from Wainwright Instruments is a Low Pass RF Filter with Frequency DC to 45 / 50 MHz, Stopband Frequency Chosen Fco x 1.125 to 3 GHz, 3 dB Cutoff Frequency Choice of 45 to 50 MHz, Insertion Loss 1.05 to 1.55 dB, Rejection 40 dB. Tags: Module with Connector, Lumped Component Filter, Chebyshev Filter. More details for WLJ9-45-50-40-3000-100 can be seen below.