Ruler 3000 is a free Chrome add-on developed by uncapit. It provides a simple and effective way to align items on a web page by displaying a line that can be used as a ruler. With Ruler 3000, you can easily compare the positions of different DOM elements and ensure precise alignment.

The add-on offers two main features: a horizontal line and a vertical line that follows the mouse pointer. The horizontal line spans the entire width of the page, while the vertical line moves dynamically with your mouse movements. These lines serve as visual guides, allowing you to visually compare the positions of various elements on the page and easily align them.

Ruler 3000 is particularly useful for web designers and developers who need to align elements accurately and maintain a consistent layout. It eliminates the need for manual measurements or guesswork by providing a convenient visual reference. With its intuitive interface and straightforward functionality, Ruler 3000 is a valuable tool for anyone working on web design or development projects.