Tricep overhead extension for arms is another dumbbell exercise for toning and strengthening triceps. The first variation of the exercise is single hand behind your head. In this variation, hold dumbbell on right hand and take it behind close to your left ear positioning the dumbbell vertically. Make sure that dumbbell remains slightly above the shoulder, and there is some space between the ear and the arm. Extend yourarm entirely at a 90 degree angle and bring it back to the starting position. Don’t rest your head on the arm and after recommended repetitions, switch to the other arm. In addition, you can also hold extending arm with free hand for more repetitions.