This mod is a patch to bring the armor values of the various pieces of equipment in the game closer to those in the Realistic Battle Mod. In other words, it will make the game more realistic. There are two versions of this mod, one slightly OP and one not. The latter is the one that is available in the game and is the one that I have tested and found to work well. 

The installation process is pretty simple and you will not need any other tools to install it. You will only need to download it and install it in the game.