The FN-4703W from Filtronetics is a Band Pass Filter with Frequency 121.45 to 121.55 MHz, Bandwidth ±50 KHz, Center Frequency 121.5 MHz, Insertion Loss 6 dB, Power 0.001 W. Tags: Module with Connectors, Surface Mount, Drop-In, Crystal Filter. More details for FN-4703W can be seen below.