UDim2

Commonly found in:
Any GUI element.

Use:
Stores Information relating to the size and position of GUI elements, going in the order of xscale, xoffset, yscale, yoffset.

Other information:
XScale and YScale control how large an element is relating to it's parent. The numbers can range from from any number, but the usual numbers will go from 0 to 1, i.e 0.1, 0.2, 0.3, etc. 1 will have the element fill it's entire parent, and 0 will make it disappear.

XOffset and YOffset are rarely used and almost never needed, since XScale and YScale will do everything as well as keep the elements relative to each users' screen resolution. In the off-chance that you do need to use XOffset and YOffset, it will move your element by pixels, relative to the top left of your screen.

Example:
local txtbtn = Instance.new("TextButton") txtbtn.Parent = Frame txtbtn.Position = UDim2.new(0.2, 0, 0.2, 0) txtbtn.Size = UDim2.new(0.8, 0, 0.8, 0) This makes a gigantic text button, filling the lower right part of the screen.