Seated Overhead Dumbbell Tricep Extension

Setup
Sitting on an upright bench, position one dumbbell overhead with both hands gripping together on the plate around the handle.
Movement Instructions
Keeping upper arms in place overhead, lower forearms behind upper arm by flexing elbows lowering the weight behind your head until elbows fully flexed. Raise dumbbell overhead by extending elbows while hyperextending wrists until back to starting position. Return and repeat.
Comments
Keep elbows in the same place throughout the movement, do not let them flex outwards to help movement.