The WLK3-3000-5500-40-11000-20 from Wainwright Instruments is a Low Pass RF Filter with Frequency DC to 3 / 5.5 GHz, Stopband Frequency Chosen Fco x 2 to 11 GHz, 3 dB Cutoff Frequency Choice of 3 to 5.5 GHz, Insertion Loss 0.2 to 0.25 dB, Rejection 40 dB. Tags: Module with Connector, Lumped Component Filter, Chebyshev Filter. More details for WLK3-3000-5500-40-11000-20 can be seen below.