The WLK9-30-35-40-6000-20 from Wainwright Instruments is a Low Pass RF Filter with Frequency DC to 30 / 35 MHz, Stopband Frequency Chosen Fco x 1.125 to 6 GHz, 3 dB Cutoff Frequency Choice of 30 to 35 MHz, Insertion Loss 1.45 to 2.25 dB, Rejection 40 dB. Tags: Module with Connector, Lumped Component Filter, Chebyshev Filter. More details for WLK9-30-35-40-6000-20 can be seen below.