Hi Paul, sorry for the confusion. This handrail fitting only matches 6210 handrail. That handrail is sold online only, and not in Home Depot stores. If you purchased 6010 handrail in a store, look for item #206685728. That may be what you need.
With any handrail profile we sell on HomeDepot.com, remember that the second digit of the handrail model # must match the second digit of the handrail fittings model #. For example, to match 6010 handrails, your fitting model number for that rail would be 7047 fitting.
If you have additional questions, we'll reply as quickly as we can. Thank you.