The WLJE4-10-20-40-8000-1 from Wainwright Instruments is a Low Pass RF Filter with Frequency DC to 10 / 20 MHz, Stopband Frequency Chosen Fco x 1.08 to 8 GHz, 3 dB Cutoff Frequency Choice of 10 to 20 MHz, Insertion Loss 1 to 2.1 dB, Rejection 40 dB. Tags: Module with Connector, Lumped Component Filter, Chebyshev Filter. More details for WLJE4-10-20-40-8000-1 can be seen below.