As mentioned above, 6 mm hex driver and adjust up or down, best lined up on the flat against a wall or garage door. This also works for driving on the continent, usually 1.5 to 2 turns from normal setting, but it only takes the beam pattern from flicking up on the left (ie highlighting the kerb) to flat, it does not then flick up on the right, but saves truck loads of cash going to the stealer.