The EMA4D1237P40D50D from ECHO Microwave is a Band Pass Filter with Frequency 1.22 to 1.26 GHz, Insertion Loss 2 dB, Rejection 50 dB @ 760MHz, Return Loss 14 dB. Tags: Surface Mount, Ceramic, Ceramic Filter. More details for EMA4D1237P40D50D can be seen below.