Why does this appear in SOLO but not in the actual game?

Ok, so this script is not actually mine, it is builderman's, but i edited it, and made my own attachments to it, but for some reason it only works in SOLO play in studio, Why is that!!! here is the script

--Basics of this script was taken from Builderman's ROBLOXtablet --yogipanda123

local gui = script.Parent.ScreenGUI:Clone()

function Equip()
    gui.Parent = game.Players.LocalPlayer.PlayerGui
end

function Unequip()
    gui.Parent = nil
end

script.Parent.Equipped:connect(Equip)
script.Parent.Unequipped:connect(Unequip)

Thanks