Design Patents only cover a unique "look" of a product. However, that look will only be protected if it has absolutely no functional value to it. If the look has a unique purpose in how it works, then it will have to be filed as a Utility Patent.

One example of a Design Patent is the bottle design for Ultra Premium Vodka by Vertikal. This design is dubbed as the "world's first neckless bottle". Note that the fact that this bottle does not have a neck does not lend itself to better handling, pouring, or other distribution of vodka beverages. In other words, the "look" of the bottle is definitely unique. However, the "look" of the bottle does not have any realy functional advantages at all.

Design Patents are given a term of 14 years from the filing date of the Patent Application.