## Common ground
All options are anti-rust or anti-corrosion preparations based on lubricants or chemical agents.
## Options at a glance
**2710 – High petroleum oil content**
- **Defining trait:** Contains 70% or more petroleum or bituminous mineral oils by weight.
- **Typical examples:** Rust-preventive oils, heavy-duty lubricating greases.
- **Best fit when:** The product is primarily a petroleum-based lubricant with rust-inhibiting additives.
**3403.19 – Low petroleum oil content**
- **Defining trait:** Contains less than 70% petroleum or bituminous mineral oils by weight.
- **Typical examples:** Light-duty rust-preventive oils, semi-synthetic lubricants.
- **Best fit when:** The product has a significant non-petroleum base but still uses lubricant properties.
**3403.99 – No petroleum oils**
- **Defining trait:** Contains no petroleum or bituminous mineral oils.
- **Typical examples:** Water-based rust inhibitors, plant-oil-based lubricants.
- **Best fit when:** The product is fully non-petroleum and relies on alternative base materials.
**3824.99 – Chemical action (e.g., phosphoric acid)**
- **Defining trait:** Acts chemically (e.g., via passivation or conversion coating) to prevent rust.
- **Typical examples:** Phosphating solutions, rust converters, chemical rust inhibitors.
- **Best fit when:** The product forms a protective chemical layer on metal surfaces.
## Key differences
| Option | Base Material | Oil Content | Action Mechanism |
|--------|----------------|--------------|--------------------|
| 2710 | High petroleum oil | ≥70% | Physical barrier |
| 3403.19| Low petroleum oil | <70% | Physical barrier |
| 3403.99| No petroleum oil | 0% | Physical barrier |
| 3824.99| Chemical agent | N/A | Chemical reaction |
## How to choose
- Does it contain 70% or more petroleum/bituminous oils? → 2710
- Does it contain less than 70% petroleum oils but still has oil-based lubricant properties? → 3403.19
- Is it completely free of petroleum oils? → 3403.99
- Does it work by chemical reaction (e.g., phosphoric acid, passivation)? → 3824.99
## Overlaps & pitfalls
A product may combine physical and chemical action (e.g., a phosphoric acid-based coating with some oil). In such cases, prioritize the **main function**: if it chemically treats metal, use 3824.99; otherwise, follow oil content rules. The term “lubricant” applies only to options 2710, 3403.19, and 3403.99—do not apply it to chemical inhibitors unless explicitly stated