JC> The tag says 148-174 megs.  Will these go to 145 by chance ?
 JC> They are model 4003.   Have 1 TX and 2 REC.
Model 4003 is just a bandpass cavity, not a duplexer.  However, if you
put 4 together, with preferably factory cable harnesses, you will have 
a duplexer.  
It should go 145, but I doubt you can get the .6 Mhz split you will need
for HAM bands with just bandpass cavities.  You will most likely need
some reject cavities also.
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