For years I have had an old Elgin pocket watch in my possession, given to me by my dad since it was broken. After some thought I have taken it to pieces to see how it worked, since it was definitely broken. Upon inspection I now know which parts are no longer functioning. 
I can find most of the parts on the Internet but unfortunately I can't find a hairspring for it... It needs to be for an Elgin size 18 pocket watch, if anyone can help it would be greatly appreciated.

Thank you
Tom