The new design of the Hario Slim Pro Coffee Mill features a ceramic grinder burr and a reinforced hexagonal crank handle. 
With the previous Slim Plus, the grind size was adjusted from the top of the grinder, after taking off the handle and the stopper. With the Slim Pro, the grind size is adjusted from the bottom of the burr set. To adjust, simply unscrew the glass container from the bottom. On the bottom of the burr set, turn the knob left or right to adjust, holding crank handle to keep the burrs stable.