Type 2 hair includes light to very wavy hair patterns. The waves and curls in type 2 hair form in the shape of an "S" and typically stick close to the head. Wavy hair won't bounce up, even when layered.
Type 2a is gently, slightly "s" waved hair that sticks close to the head; it won't bounce up, even when it is layered. 2a hair tends to be fine, thin and very easy to handle. It is also generally easily to straighten or curl. Type 2a hair tends to have quite a bit of sheen. Your best bet is to use lighter products such as mousses, lotions or gels that enhance the curls, but don't weigh them down.
With this hair type, the wave or curl forms throughout the hair in the shape of the letter "s". Type 2b hair sticks close to the head; it won't bounce up, even when it is layered. Type 2b hair often has a nice sheen. It has a bit more wave in it than Type 2a has. This hair type is a little resistant to styling, and it has a tendency to frizz. Use lighter products such as mousses or gels that enhance the curls, but don't weigh them down.
Type 2c is thicker, coarser wavy hair that is composed of a few more actual curls, as opposed to just waves. Type 2c hair tends to be more resistant to styling and will frizz easily. Type 2 wavies tend to use a lot of gel to style and manage frizz. Many with 2c hair have an underlayer of straight hair, while others have an underlayer that's more ringlet-y and curly.