A method of measuring a characteristic of a skin, including varying an air pressure in a chamber positioned adjacent to a skin, in which the chamber has an opening that exposes the skin to changes in the air pressure in the chamber. A gear wheel transmission is established between the nut and the injection button. A wiping device is provided to remove excess cleaning fluid. The chip breaker portion is provided at varying distance from the associated cutting edge. The sleeve is preferably worm-gear driven for accurate position control. The cable retention element is attached to the cable and is at least partially disposed within the housing.