The WLJ3-300-400-60-3000-100 from Wainwright Instruments is a Low Pass RF Filter with Frequency DC to 300 / 400 MHz, Stopband Frequency Chosen Fco x 2.7 to 3 GHz, 3 dB Cutoff Frequency Choice of 300 to 400 MHz, Insertion Loss 0.2 to 0.3 dB, Rejection 60 dB. Tags: Module with Connector, Lumped Component Filter, Chebyshev Filter. More details for WLJ3-300-400-60-3000-100 can be seen below.