What bike is this? Need to find derailleur hanger I know derailleur hangers are specific to their frames, and since there are numerous brands with numerous models, I would need to know which one mine is before I can start searching for it, right?

What I know about the bike:


Brand: Giant
Model: Boulder
Frame: Size L, 6061 ALUXX Butted Aluminum


What I need to know:


The year this one was brought to market
Info on how to search for a derailleur/mech hanger (I fiugre the above will be relevant to that)


I have found this, but how can I be sure it's the right one?







Any help would be much appreciated!
It looks like you need this one (Wheels Mfg 21, which they list for Giant Boulders of all years).

If you took the bike to your bike shop, they'd compare the derailleur hanger visually to other ones used by Giant and see there is nothing else like it. Or pull up a chart from Wheels Mfg and look up what bike it is and which ones could fit. 

So it looks like the one you have found on eBay is the right one.