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 21 Orthopaedic appliances; splints, etc; artificial parts of the body, etc 90 21 50 Pacemakers for stimulating heart muscles, excluding parts and accessories Commodity Code Description 90 21 50 00 Pacemakers for stimulating heart muscles, excluding parts and accessories