The ECA3975P500D45A from ECHO Microwave is a Band Pass Filter with Frequency 3.73 to 4.23 GHz, Insertion Loss 2 dB, Rejection 45 dB @ 1400 to 3545MHz, Ripple 0.5 dB, Return Loss 15 dB. Tags: Cavity Filter. More details for ECA3975P500D45A can be seen below.