Invisalign is a sequence of custom-fabricated aligners that are moulded to your teeth. They are virtually invisible and fit snuggly around your teeth. Each aligner is worn for 1-2 weeks and then switched for a new set to gradually and sequentially move your teeth into their desired position.
Some advantages of Invisalign to tradition braces including being able to take out the aligners to brush and floss your teeth without having to deal with all the hardware. Also, you no longer have to avoid certain foods like you would with brackets and wires as you remove the aligners during eating and drinking.
Checkout the Invisalign website for even more information: