The WLJE5-4-5-80-8000-0.01 from Wainwright Instruments is a Low Pass RF Filter with Frequency DC to 4 / 5 MHz, Stopband Frequency Chosen Fco x 1.23 to 8 GHz, 3 dB Cutoff Frequency Choice of 4 to 5 MHz, Insertion Loss 0.9 to 1.3 dB, Rejection 80 dB. Tags: Module with Connector, Lumped Component Filter, Chebyshev Filter. More details for WLJE5-4-5-80-8000-0.01 can be seen below.