You start by going to the Husqvarna web site and downloading the parts list
Search the site to find products, parts and accessories from Husqvarna, or frequently asked questions, operator's manuals or how-to videos.
www.husqvarna.com
Then you find the part number of your belt
Then you go to Gates interchange web site and search that part number, remove the - and any spaces so it looks like what Star has posted & not 532 13 09-69 as it appears in the parts book
Follow the links and get the REAL specs
www.gates.com
I am yet to come across a belt that is not listed .
Also note that while it is listed as an A section, it is not a standard 1/2" wide A belt being listed at 14 mm not 12.5 mm
Also note that it is a different length so it appears that somewhere along the line an incorrect superseding number has slipped into the system as 587 27 01-01is not the same as 532 13 09-69 and more than one site has the incorrect information on it .