It doesn't seem to do anything when I equip it in my baubles slot, I do have mana storage in my inventory so it should be working. It is supposed to increase your reach range that you can interact/hit stuff at but it doesn't I have not tested in single player yet but I will later today. Botania mod btw if you don't already know
Try taking it off/on a few times also it only really works with hitting/breaking/right clicking blocks, things like tools and wrenches might not follow the far reach
Update- Did some testing yesterday and In both single player and multiplayer, no matter how many times I re-equip it or relog with is on, the only thing it does is increase the range that waila identifies things. I can't break or place blocks any further then normal. Correct me if I'm wrong but this means that it's an issue with the mod and not MYM. So I'll close this issue