The AM1800B1688 from Anatech Electronics is a Band Pass Filter with Frequency 1.55 to 2.05 GHz, Bandwidth 500 MHz, Center Frequency 1800 MHz, Insertion Loss 2.5 dB, Rejection 40 to 49 dB. Tags: Surface Mount, Ceramic, Ceramic Filter. More details for AM1800B1688 can be seen below.