Try this site:
http://www.ironcompany.com/index.asp?PageAction=VIEWPROD&ProdID=3712
Just make sute what is your bar and if it will fit. These on the picture are for Olimpic bars and they are 2". My bar is 1" and they sent me collars that would fit mine. Contact them first. I ordered them, they are EXTREMELY EASY to open and close and I am very very happy. I cant imagine going back to sprong collars ever again!
Best: Krasy