Quick disconnects are (as the name would imply) connectors that can be connected and disconnected quickly. These seal very well (no drips at all) and support liquid flow in either direction. The male end is simply a post with a locking groove in it. Mates with the female end to form a locking seal.
Note: Always purchase the male and female ends from the same manufacturer to ensure proper fit. Improper fit can lead to leaks (fit too loose) or damaged o-rings / o-rings that get dislodged (fit too tight).