Dumbbell pronate-grip triceps extension

Sit on a bench or chair with your back straight and feet flat on the ground. Hold a dumbbell with both hands, palms facing down, and extend your arms straight up overhead. Keeping your upper arms close to your head and elbows pointing forward, slowly lower the dumbbell behind your head by bending your elbows. Pause for a moment, then extend your arms back up to the starting position. Repeat for the desired number of repetitions.