Which Shimano freehub body do I need?

[Tates]

I have to replace the Shimano freehub body on my 2011 GT Aggressor XC2 hard tail mountain bike, which has a 9 speed casset. However, I can't workout from all the on-line shops such as ChainReaction which specific 9 speed Shimano model I need, as there seems to load of slightly diffrently models, or at least they have slighty diffrent reference numbers. If I purchase any Shimano 9 speed mountain bike specific freehub will this be interchangable with the one I currenty have on my GT, or do I have to purchase a very specific Shimano 9 speed freehub?

[1FJEF]

It follows the hub. If the model# of the hub is visible, do a search for a Shimano FH-XXXXX freehub body & you'll find what fits in Shimano Tech Docs, and for sale all over. Amazon should have it.