How Weapon & Armor Upgrading Works in Diablo 2
On this page I will go into detail about exactly how the item upgrading Horadric Cube recipes work in Diablo 2. The first thing you need to learn about to understand these recipes is the fact that Diablo 2 has multiple tiers of armor and weapons. They start with Normal and then go to Exceptional followed by Elite being the best.
Each tier of armor and weapons has a set of icons that look exactly the same; the only thing that changes between these items is the base stats that they hold. The Diablo 2 wiki in my opinion does the best job of explaining this. Below are some screenshots that I took from their website.
Example of 'Normal' Armor in Diablo 2.
Example of 'Exceptional' Armor in Diablo 2.
Example of 'Elite' Armor in Diablo 2.
As you can see from the pictures, the icon of each item looks identical from Normal all the way to Elite. The only things that change on the items are the name, requirements and the stats. Essentially what each of the Horadric Cube recipes do that 'upgrade' an item is they boost it up one whole quality level. So if you start with a Studded Leather piece of armor, use the upgrade recipe on it and you'll make it into a Trellised Armor. One more upgrade and it will become a Wire Fleece.
Using the Iceblink Splint Mail Unique item I did this recipe once to show you exactly how it will work when used on a piece of armor. The Splint Mail base item became a Russet Armor and the Strength requirements went up along with the required level. Along with this, the base Defense on the item went up. Nothing else changed.
Below you will find more examples of these recipes in action
Treads of Cthon Chain Boots become Mesh Boots.
Heavy Boots got upgraded to Sharkskin Boots.
Sharkskin Boots got upgraded to Scarabshell Boots.