This casual pairing of a white flannel long sleeve shirt and a white flannel long sleeve shirt comes in useful when you need to look casually stylish in a flash. Put an elegant spin on your getup with a pair of tan suede derby shoes. So as you can see, this outfit is a really great choice, especially for awkward transition weather, when the mercury is dropping. This is a good-looking and mature ensemble for 20-year-old gents.