The EMA4C3750P100C30B from ECHO Microwave is a Band Pass Filter with Frequency 3.7 to 3.8 GHz, Insertion Loss 1.5 dB, Rejection 30 dB @ 3220 to 3320 MHz, Return Loss 12 dB. Tags: Surface Mount, Ceramic, Ceramic Filter. More details for EMA4C3750P100C30B can be seen below.