Hold a dumbbell in each hand with a pronated grip. Either sit into a partial squat and rest the forearms on the thighs, or kneel and support the forearms on a bench, keeping the hands slightly below the elbows.
 
Allow your wrists to flex, then extend them to lift the dumbbells back up as far as possible, and lower again under control.
 
Purpose
The dumbbell wrist extension strengthens the wrist and helps keep the wrist healthy by adding some balance to the large volume of wrist and finger flexor work in weightlifting. Using dumbbells increases the demand on wrist control and stability, and helps develop and maintain symmetry side to side.
 
Programming
Generally sets of 10-30 are appropriate.