| 511 | Ordinary Portland Cement | Company Product |
| 512 | Organic Amendments | Company Product |
| 513 | Organic Composition | Company Product |
| 514 | Organic Essential Oils | Company Product |
| 515 | Organic Food | Company Product |
| 516 | Organic Material Removal | Company Product |
| 517 | Organic Supplements | Company Product |
| 518 | Organicoil | Company Product |
| 519 | Organisation Charts | Company Product |
| 520 | Organization | Company Product |
| 521 | Organs Agents & Distributors | Company Product |
| 522 | Oriental Goods Retailers | Company Product |
| 523 | Oriented Polypropylene Tapes | Company Product |
| 524 | Orifice Flanges | Company Product |
| 525 | Orifice Plate Flanges | Company Product |
| 526 | Orifice Plates | Company Product |
| 527 | Orp-Alkaline Tester | Company Product |
| 528 | Orp Analysers | Company Product |
| 529 | Orp Analyzers | Company Product |
| 530 | Orp Controllers | Company Product |
| 531 | Orp Meter | Company Product |
| 532 | Orp Meters | Company Product |
| 533 | Orp Monitors | Company Product |
| 534 | Orp Portable Handheld Meters | Company Product |
| 535 | Orp Probes | Company Product |
| 536 | Orp Sensors | Company Product |
| 537 | Orp Test Probes | Company Product |
| 538 | ORP Transmitters | Company Product |
| 539 | Orp650b Bluetooth Orp | Company Product |
| 540 | Orthodox Catholic Churches | Company Product |