The WLJE4-0.2-0.4-40-8000-0.01 from Wainwright Instruments is a Low Pass RF Filter with Frequency DC to 0.2 / 0.4 MHz, Stopband Frequency Chosen Fco x 1.08 to 8 GHz, 3 dB Cutoff Frequency Choice of 0.2 to 0.4 MHz, Insertion Loss 0.7 to 1.8 dB, Rejection 40 dB. Tags: Module with Connector, Lumped Component Filter, Chebyshev Filter. More details for WLJE4-0.2-0.4-40-8000-0.01 can be seen below.