The FN-1948W from Filtronetics is a Band Pass Filter with Frequency 0.4523 to 0.4574 MHz, Bandwidth ±0.0012 MHz, Center Frequency 0.4535 MHz, Insertion Loss 6 dB, Rejection 60 dB. Tags: Drop-In, Module with Connectors, Crystal Filter. More details for FN-1948W can be seen below.