From BitSplash Software:
Exact Mouse is a utility to aid in the use of graphic design, mechanical engineering, and Web and application development. Specifically, Exact Mouse enhances the functionality of your mouse by enhancing user control over mouse movements, generating customizable rulers and grids, and saving specific locations on the screen. Custom layouts of these tools can be saved and recalled via buttons or hot keys. Additionally, Exact Mouse provides tools to aid in design including a magnifying window and a color-choosing window.