The people with craggy face can wear shield sunglasses, and they're the perfect match. People with round face should never think about wearing shield sunglasses, because that would make the face seems more round.
You'd better choose sunglasses at a real store, because you can find out what the perfect one for you. Then you can buy the same type on the internet.
Usually the small face shape will not be suitable with shield sunglasses. Whatever other types of the face shape could be suitable with this kind of sunglasses. Talking about two distinctive features of shield sunglasses, we could know that there are wide arms and a continuous frame. This kind of sunglasses is suitable for both men and women, protecting our eyes from the sun which may contain the strong uv rays and so on. There are many celebrities tending to wear the shield sunglasses, like Rihanna and Lady Gaga. This kind of sunglasses is so cool at the whole design and excellent at the quality if you like to wear. They are known as the wraparound sunglasses which mean that they're perfect for long time wearing in the sun. However, they could be regarded as the athletic type. If you like to do the afternoon runs and games of balls, you could just take this type of the sunglasses into consideration.