The AB838B904 from Anatech Electronics is a Band Pass Filter with Frequency 804.5 to 871.5 MHz, Bandwidth 67 MHz, Center Frequency 838 MHz, Insertion Loss 1.0 dB, Upper Rejection 40 dB @ 1600-2500 MHz. Tags: Module with Connectors, Cavity Filter. More details for AB838B904 can be seen below.