The AM1542S921 from Anatech Electronics is a Band Pass Filter with Frequency 1.52 to 1.55 GHz, Bandwidth 34 MHz, Center Frequency 1542 MHz, Insertion Loss 3.0 to 4.35 dB, Upper Rejection 30 dB 1600-1650 MHz. Tags: Surface Mount, RF SAW Filter. More details for AM1542S921 can be seen below.