These rails are not perfect but they are really good. Vevor had the cheapest price and free shipping so I was worried these might look like they were built by monkeys. Instead the smooth steel rods were clean, smooth strong and defect free. Lightly oiled and wrapped in plastic and foam to prevent rust or damage. The rollers are exactly what you would expect. An Aluminum cast piece that has been tapped for threads with a bearing added into the middle. They roll a little rough until you put a load on them then they quiet down and ride smooth. Don't want to oil them as it will mix with saw dust in my shop. The aluminum feet to the rods are probably the worst part of them. They are straight and flat but the mounting holes were drilled by hand. So they are not precisely located, spaced or even sized. Not a problem for me. So I will give it a 5 star as the price fits.