The dumbbell snatch is a movement that helps train “explosiveness” in an athlete without the availability of a barbell with rubber plates.  The movement takes a dumbbell from the hang or ground position and moves it overhead in one motion, without stopping at the shoulder as is seen in the dumbbell clean.  The key to the movement is to be quick.  Using the hips to “jump” or “pop” the weight overhead is key, not using the shoulder to lift the weight overhead.  When the dumbbell reaches it’s max height (may or may not be overhead at this point), the athlete then drops under the dumbbell and receives it with a straight, locked out arm.  Then, all that needs to be done is to stand up to full lock out.  Here are some videos on dumbbell snatches.