Section 18 Optical, photographic, cinematographic, measuring, checking, precision, medical or surgical instruments and apparatus; clocks and watches; musical instruments; parts and accessories thereof 90 Optical, photographic, cinematographic, measuring, checking, precision, medical or surgical instruments and apparatus; parts and accessories thereof 90 18 Instruments and appliances used in medical, surgical, dental... 90 18 41 Dental drill engines, whether or not combined or single base with other dental equipment Commodity Code Description 90 18 41 00 Dental drill engines, whether or not combined or single base with other dental equipment