| 91138 | Offices, trademark, administrative services related to the operation of | |
| 88767 | Office-type binding equipment manufacturing services | |
| 88774 | Off-road dumping trucks manufacturing services | |
| 41536 | Offsets, aluminium, for tubes or pipes | |
| 41516 | Offsets, copper, for tubes or pipes | |
| 42999 | Offsets, lead, for tubes or pipes | |
| 41524 | Offsets, nickel, for tubes or pipes | |
| 41292 | Offsets, of cast iron, for tubes or pipes | |
| 41293 | Offsets, of iron or steel (excl. cast iron and steel), for tubes or pipes | |
| 41293 | Offsets, of stainless steel, for tubes or pipes | |
| 42999 | Offsets, tin, for tubes or pipes | |
| 42999 | Offsets, zinc, for tubes or pipes | |
| 48243 | Ohmmeters | |
| 86211 | Oil and gas fires, extinguishing of | |
| 86211 | Oil and gas, extraction of | |
| 86211 | Oil and gas, services incidental to the extraction of | |
| 21732 | Oil foots | |
| 88765 | Oil heating equipment manufacturing services | |
| 34110 | Oil of mirbane | |
| 83323 | Oil or gas pipelines and related works, local, corrosion control programmes for | |
| 83323 | Oil or gas pipelines and related works, local, electrical engineering design services for the construction of | |
| 83323 | Oil or gas pipelines and related works, local, geotechnical engineering services for the construction of | |
| 83323 | Oil or gas pipelines and related works, local, groundwater assessment for the construction of | |
| 83323 | Oil or gas pipelines and related works, local, integrated engineering services for the construction of | |
| 83323 | Oil or gas pipelines and related works, local, mechanical engineering design services for the construction of | |
| 83323 | Oil or gas pipelines and related works, local, other engineering services for the construction of | |
| 83323 | Oil or gas pipelines and related works, local, specialty engineering design services for the construction of | |
| 83323 | Oil or gas pipelines and related works, local, structural engineering design services for the construction of | |
| 83323 | Oil or gas pipelines and related works, local, structural failure investigation of | |
| 83323 | Oil or gas pipelines and related works, local, technical inspection services during the construction of | |
| 83323 | Oil or gas pipelines and related works, local, undertaking contamination studies of | |
| 83323 | Oil or gas pipelines, long-distance, corrosion control programmes for | |
| 83323 | Oil or gas pipelines, long-distance, electrical engineering design services for the construction of | |
| 83323 | Oil or gas pipelines, long-distance, geotechnical engineering services for the construction of | |
| 83323 | Oil or gas pipelines, long-distance, groundwater assessment for the construction of | |
| 83323 | Oil or gas pipelines, long-distance, integrated engineering services for the construction of | |
| 83323 | Oil or gas pipelines, long-distance, mechanical engineering design services for the construction of | |
| 83323 | Oil or gas pipelines, long-distance, other engineering services for the construction of | |
| 83323 | Oil or gas pipelines, long-distance, specialty engineering design services for the construction of | |
| 83323 | Oil or gas pipelines, long-distance, structural engineering design services for the construction of | |