One click equipment set, specialization and talent changer.
Ever forgot to switch your equipment when you changed your specialization? MultiSpec aims at this and gives you a new button within your character frame which lists all your equipment sets and let you switch specialization, talents and the equipment set with one click.
In the options you can define which specialization is associated with an equipment set and optionally you can define which talents shall be used with this set.
Type /ms or /multispec for options or go to the Blizzard Addon options and click on MultiSpec.
You can change equipment sets/spec via macro. "/ms equip yourset" will do this.