Originally Posted by b7spectra
The XTL would have to be an "A4" model radio to accept the head. All depends on the model. Many jurisdictions were able to keep their 5 & 7 heads when they upgraded from Spectras to XTLs. Just Google: xtl with spectra head .
The XTL2500 was never offered in anything but an M5 head.
To upgrade, they would have to have had Astro Spectra's with a W head (A series heads are for analog Spectra's) and the radio they would be upgrading to would have been an XTL5000.
Bottom line, the OP needs an M5 head or an O5 head with some minor hacking.