Optional JRC crystal filters are as follows:
JRC##         NDK##       Bandwidth/-6dB
========  ===========  ===============
CFL-231     (YF455FM)     0.3 kHz
CFL-232     (YF455DQ)     0.5 kHz
CFL-233     (YF455DE)      1.0 kHz
CFL-218A   (YF455EBF)     1.8 kHz
CFL-251     (YF455EB)       2.4 kHz
CFL-316                         0.5 KHz (9 MHz IF) 
CFL-317                         1.8 kHz (9 MHz IF)  
CFL-318                         2.7 kHz (9 MHz IF) (Standard on JST-245)
These JRC filters are DC coupled.
Need 0.01 uF in series to fit with other (ICOM) receivers.
Murata 455 kHz filters
CFJ455K13      2.6 kHz 
CFK455J         3.6 kHz
CFW455IT       5.1 kHz 
CFU455G         9.5 kHz