[Premium-Rx] JRC filter question

[GandalfG8 at aol.com]

Hi All
 
I have recently bought a JRC NRD525 receiver that has been fitted with an  
additional filter.
I have the original receipt for fitting the filter which lists  it as a 
CFL251 with 2.4KHz bandwidth.
However, the filter itself is marked YF455EB.
The manual doesn't list this as an option but does list a YF455EBF, (  
CFL218A),  which has a 1.8KHz bandwidth.
I can't find anything online and am not sure if the F is  significant so 
would be grateful if anybody could tell me if the  YF455EB is indeed equivalent to 
a CFL251 with 2.4KHz bandwidth to save me having  to measure it to satisfy my 
curiosity.
 
regards
 
Nigel Clarke
G8PZR