What is it?
It's a mod that caps your level.

How it works?
You will get holotape when mod first loaded. Insert it into any terminal in world, nor PipBoy. Set any level cap from 0 to 65535. Number is sets digit by digit, first tens of thousands, then thousand, then hundreds, tens and finally units. If you lose your holotape you can craft one at chem lab. If you have holotape in your inventory recipe will not be shown. Now your character will not receive any experience and stop leveling. However if you already higher that cap value mod will not delevel you (level down), becuase Beth's disabled any posibility for that.

Why?
Short version: why not?
Long version: not once i saw screenshots with character level about 260, one and half thousand hit points and complains that everything is so underpowered... I don't want end like this. That's why i made it, and i made it for myself. Just shearing in case any one feels the same.