I'm interested in purchasing a Kohler Langlade drop-in sink.

Home Depot sells this sink for $259. The item # is K-RH6626-4-0. Kohler says this item is for retail sale only.

Amazon and a couple other online merchants sell it for $375-$410. The item # is slightly different though, K-6626-4-0.

Are these identical sinks? Or do you think there might be a slight quality difference? Interestingly, the Home Depot version of the sink says that sink is manufactured with 93% recycled material whereas the non-retail version of the same sink says it uses 80% recycled material.

Any thoughts? I know the big box stores negotiate better prices but sometimes with a compromise in quality? Any thoughts?

The RH designation should indicate Right Hand - meaning that one side of the sink is slightly larger than the other. Other than that, the two different numbers are likely two sinks that are almost identical in outside shape and dimensions, depth etc.

I think your final comment is only half right. the big box stores can negotiate a better price for the same product with no compromise in quality. Where the big boxes fail is that they will only offer a limited selection as in-stock items. They can special order anything, but will no longer have a price advantage.

you will find different packaging between the depot and the plumbing wholesale warehouse. in the trades-only warehouse, who cares if it's a plain brown box? -- the markup on installation is the same.

in the home center, Kohler has to look better at Point Of Sale (the abbreviation used in business for decades is banned on most websites by the net nanny) than China Bay or CheapoPlum to get sold. so you'll find a white box with a fancy picture on it.

the box stores get that big discount by ordering 5000 sinks at a time, rather than 6.