Glider is right of course, but a good source is your friendly neighborhood hardware store, generally affiliated with Do IT or TrueValue or others. The prices are a little better and you can pick the hardware the way you want, just bring the old one with you to make sure the length and thread pitch is correct.
I like stainless steel, even though in some cases they are more dull in finish than brand new chrome ones, but that is because I prefer the "billet" finish...