The WLJ4-3000-5000-40-8000-50 from Wainwright Instruments is a Low Pass RF Filter with Frequency DC to 3 / 5 GHz, Stopband Frequency Chosen Fco x 1.53 to 8 GHz, 3 dB Cutoff Frequency Choice of 3 to 5 GHz, Insertion Loss 0.25 to 0.35 dB, Rejection 40 dB. Tags: Module with Connector, Lumped Component Filter, Chebyshev Filter. More details for WLJ4-3000-5000-40-8000-50 can be seen below.