1. You can use it to make precise measurements on your screen.
2. You can open an image - design comp - in it and change its opacity. You can then position it over your design implementation so that you can see where elements don´t match up.

You can also use it to see how a new element might look on your website. For instance an ad placement.

Features:

• alpha fading of the image
• turn the image visibility off
• create horizontal or vertical guides
• drag the guides around
• use the guides to measure pixel distances very precisely
• use the arrow keys to move the guides - if it´s selected/red
• or use the arrow keys to move the image/window around on your desktop
• hold down the shift key to move 10 pixels at a time

Requires: Adobe AIR.