• Best For: Floor-prep crews whose 4" grinder takes a 7/8"-5/8" arbor wheel rather than a 5/8"-11 threaded one.
• Highlight: The same single-row turbo MK-504CG-1 cup wheel at 4" (102mm), supplied for the 7/8"-5/8" arbor mount.
• Expert Note: Match the mount to your machine: this is the arbor version, and the 5/8"-11 nut version of the same wheel is 158687.