The WLKE4-20-25-40-8000-1 from Wainwright Instruments is a Low Pass RF Filter with Frequency DC to 20 / 25 MHz, Stopband Frequency Chosen Fco x 1.08 to 8 GHz, 3 dB Cutoff Frequency Choice of 20 to 25 MHz, Insertion Loss 0.9 to 1.9 dB, Rejection 40 dB. Tags: Module with Connector, Lumped Component Filter, Chebyshev Filter. More details for WLKE4-20-25-40-8000-1 can be seen below.