The 800004 from Bree Engineering is a Band Pass Filter with Frequency 3650 to 4030 MHz, Center Frequency 3840 MHz, Insertion Loss 0.9 dB, Upper Rejection 30 dBc, Lower Rejection 20 to 80 dBc. Tags: Module with Connectors, Cavity Filter, Combline Filter. More details for 800004 can be seen below.