I'm not a materials engineer! But compared to the original nuts on my 5th wheel, these are much better. Attached is a photo of my original RV nuts versus these DPA D3614XL-2305 nuts. 3 new nuts from my order, only 3 included to see more angles. No wonder the fifth wheel manufacturer didn't supply great eye nuts, it took me almost 4 years to even look at my nuts. When I had to remove the wheel the last 1/3" was just a flimsy cap. All were scrunching to take it off except one that had its cap completely ripped off. So they are solid and have a bit more grip on the sides. And they arrived faster than promised.