The WLK6-30-40-60-6000-20 from Wainwright Instruments is a Low Pass RF Filter with Frequency DC to 30 / 40 MHz, Stopband Frequency Chosen Fco x 1.4 to 6 GHz, 3 dB Cutoff Frequency Choice of 30 to 40 MHz, Insertion Loss 0.8 to 1.1 dB, Rejection 60 dB. Tags: Module with Connector, Lumped Component Filter, Chebyshev Filter. More details for WLK6-30-40-60-6000-20 can be seen below.