MILWAUKEE 5196 HEAVY-DUTY DIE GRINDER - 14,500 RPM

Just purchased one of these. Finding grinding wheels that show the RPM required has become an issue. Does anybody know a site where I can purchase good stones and bit's for this tool, that operate within the tool's speed range.
This is one **** of a good machine, heavy but very strong with it. I have been using steel brushes and they remove rust like a grinding stone. Have a few cheap stones that work well but wear quickly, so I know the quality or speed is an issue.
Thank you for any help.