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, me Thereof. 90 31 Measuring or checking instruments, appliances and machines, not specified or included elsewhere in this chapter; profile projectors Commodity Code Description 90 31 10 - Machines for balancing mechanical parts 90 31 20 - Test benches 90 31 41 - - For inspecting semiconductor wafers or devices (including integrated circuits) or for inspecting photomasks or reticles used in manufacturing semiconductor devices (including integrated circuits) 90 31 49 - - Other 90 31 80 - Other instruments, appliances and machines 90 31 90 - Parts and accessories