SETUP: Lie flat on the bench and hold a dumbbell above at shoulder level. Turn the weight so your palms are facing your lower body, this will make the dumbbell easier to hold.
REP: Keeping your elbow locked in place, let your arm drop in a controlled manner until you create a 90 degree angle. The dumbbell should be sitting near the opposite shoulder now. Drive the weight back up by squeezing your triceps hard.