The WLK12-1000-3500-40-11000-20 from Wainwright Instruments is a Low Pass RF Filter with Frequency DC to 1 / 3.5 GHz, Stopband Frequency Chosen Fco x 1.06 to 11 GHz, 3 dB Cutoff Frequency Choice of 1 to 3.5 GHz, Insertion Loss 0.9 to 1.9 dB, Rejection 40 dB. Tags: Module with Connector, Lumped Component Filter, Chebyshev Filter. More details for WLK12-1000-3500-40-11000-20 can be seen below.