The ceramic grinding mechanism activates with a smooth clockwise motion. Only use when filled with either black peppercorns or dry rock salt up to 4mm in size. Do not fill with sea salt, wet salt, dried wet salt or pink peppercorns. The tighter the grind adjustment knob is screwed, the finer the grind - please avoid overtightening to prevent damage to the ceramic mechanism. Do not leave in prolonged direct sunlight. Wipe with a soft, damp cloth; do not immerse in water. Beautifully gift boxed. Height: 9.25"H x 2.16" Square (including screw knob)