5 Add-ons in this Collection
Firebug by Joe Hewitt, Jan Odvarko, others
Collector's Note The Tool You Must Have
The Web Developer extension adds various web developer tools to the browser.
Collector's Note To Be Honest, i just only use the ruler, the other than that. Firebug can handle it
Advanced Eyedropper, Color Picker, Gradient Generator and other colorful goodies...
Collector's Note For take hexadecimal color when you make a design, best combine with firebug