Triceps Kickbacks from BOSU
This exercise will add an element of instability causing your core to kick in and stabilize your body while you perform the exercise in addition to shaping your triceps.
Stand your left foot on the dome part of the BOSU. Place the right leg on the floor in a staggered stance with the dumbbell in the right hand. Bent your elbow into your side and then kickback the dumbbell keeping your elbow into your side the whole time. Do 12-15 reps and then switch sides.