The WLK6-2000-5000-40-11000-20 from Wainwright Instruments is a Low Pass RF Filter with Frequency DC to 2 / 5 GHz, Stopband Frequency Chosen Fco x 1.26 to 11 GHz, 3 dB Cutoff Frequency Choice of 2 to 5 GHz, Insertion Loss 0.4 to 0.5 dB, Rejection 40 dB. Tags: Module with Connector, Lumped Component Filter, Chebyshev Filter. More details for WLK6-2000-5000-40-11000-20 can be seen below.