The WLKX12-3500-6000-40-18000-20 from Wainwright Instruments is a Low Pass RF Filter with Frequency DC to 3.5 / 6 GHz, Stopband Frequency Chosen Fco x 1.06 to 18 GHz, 3 dB Cutoff Frequency Choice of 3.5 to 6 GHz, Insertion Loss 1 to 2 dB, Rejection 40 dB. Tags: Module with Connector, Lumped Component Filter, Chebyshev Filter. More details for WLKX12-3500-6000-40-18000-20 can be seen below.