Here is what the copy says:

"Men's sock size 10-13, fits most shoe sizes."

From that you might expect that the socks would fit if you have size 10.5 shoes. Not true. First, sock sizes are not the same as shoe sizes (unbelievable but true), and second these socks do NOT fit "most shoe sizes." The copy should read

"Extra Large. Men's shoe size 12-15."

These socks were way to big for my size 10.5 feet. Because the curve of the heel is in the wrong place, the socks fall down and are annoying. This is a problem particularly if you walk around without shoes on.

It's too bad because the sock material seems quite good. Obviously the seller had some XXL socks to unload, and used misleading copy to do it.

I will return them, but will be out $12 in shipping fees.

Don't get these unless you have shoe size of at least 12. I tried washing in hot water, but there was no shrinkage.

While these are only an 18% Merino blend, they make up for more wool with a very nice high loft synthetic blend. For this price they are very comfortable and warm and well worth it.
If you want more merino wool, I'd recommend looking at Elders Hosiery.

Well built but too thin. You can get better pairs (thicker, more wool) at Walmart in the hunting section.