## Common ground
All options are types of stud link chains, defined by their interlocking metal links with raised studs.
## Options at a glance
**7315.81 – Iron or steel**
- **Defining trait:** Made from ferrous metal, typically strong and durable with magnetic properties.
- **Typical examples:** Industrial conveyor chains, heavy-duty security chains, motorcycle chain links.
- **Best fit when:** High strength, wear resistance, or magnetic use is required.
**7419 – Copper**
- **Defining trait:** Non-ferrous, corrosion-resistant, and electrically conductive; often used where conductivity or aesthetics matter.
- **Typical examples:** Decorative chains in art installations, electrical grounding links, antique-style jewelry.
- **Best fit when:** Corrosion resistance, non-magnetic behavior, or visual appeal is key.
**7616.9X – Aluminium**
- **Defining trait:** Lightweight, non-corrosive, and non-magnetic; ideal for applications needing low weight.
- **Typical examples:** Aerospace components, lightweight decorative chains, marine fittings.
- **Best fit when:** Weight reduction or resistance to rust in humid environments is essential.
## Key differences
| Feature | Iron/Steel (7315.81) | Copper (7419) | Aluminium (7616.9X) |
|------------------|------------------------|--------------------|------------------------|
| Weight | Heavy | Medium | Light |
| Corrosion resistance | Low (rusts) | High | Very high |
| Magnetic? | Yes | No | No |
| Conductivity | Low | High | Medium |
## How to choose
- Is the chain used in heavy-duty or industrial applications? → 7315.81
- Does it need to resist corrosion, conduct electricity, or look decorative? → 7419
- Is lightweight construction or marine use a priority? → 7616.9X
## Overlaps & pitfalls
A chain could be both non-magnetic and corrosion-resistant (e.g., copper or aluminum), but the primary material determines the HS Code. If unsure, prioritize the **main functional property**: strength (steel), conductivity/aesthetics (copper), or lightness (aluminum). No option is vague—each clearly defines material composition