Rulers 

Rulers is a utility that allows users to create rulers on their entire screen, like most common graphic editors. It can be used to measure and position objects precisely, and is useful for computer graphics, desktop publishing, and web design. It also allows users to select a screen area and take a screenshot that is automatically saved to the desktop or copied to the system clipboard. Features include unlimited ruler creation, multiple units of measurement support, auto measure, and multi-monitor support.