How to Do preacher curls with a dumbbell

This video demonstrates how to do a preacher curl with a dumbbell. you hold a dumbbell in your right hand so that the edge of the bench is under your armpit and your arm is fully extended over the bench surface. Raise the weight towards your chin, keeping your wrist locked at all times. Lower the weight in a slow and controlled manner. Then switch arms and do a set for the left arm.