## Common ground
All options are spools, bobbins, or similar supports used for holding materials like thread, wire, or tape.
## Options at a glance
**3923.40 – Made of plastic**
- **Defining trait:** Constructed from synthetic polymer materials (e.g., polypropylene, nylon).
- **Typical examples:** Plastic thread spools, filament reels for 3D printers, packaging bobbins.
- **Best fit when:** Lightweight, durable, moisture-resistant, or low-cost use is needed.
**4421.99 – Made of wood**
- **Defining trait:** Crafted from natural wood (e.g., pine, birch), often unfinished or lightly treated.
- **Typical examples:** Wooden spools for yarn, traditional textile bobbins, artisanal packaging reels.
- **Best fit when:** Aesthetic appeal, eco-friendliness, or traditional craftsmanship is valued.
**4822 – Made of paper or paperboard**
- **Defining trait:** Constructed from paper-based materials, often corrugated or folded.
- **Typical examples:** Paper core tubes for tape, cardboard spools for film, disposable packaging reels.
- **Best fit when:** Low cost, single-use, or recyclable applications are required.
**7017.90 – Made of glass**
- **Defining trait:** Manufactured from transparent or translucent glass, typically rigid and non-reactive.
- **Typical examples:** Glass spools for delicate threads in labs, specialized industrial reels.
- **Best fit when:** Chemical resistance, clarity, or high precision is essential.
**7326.90 – Made of iron or steel**
- **Defining trait:** Fabricated from ferrous metals, offering high strength and durability.
- **Typical examples:** Heavy-duty wire spools, industrial cable reels, machine tool bobbins.
- **Best fit when:** High load capacity, long-term use, or mechanical robustness is required.
## Key differences
| Feature | Plastic | Wood | Paperboard | Glass | Iron/Steel |
|------------------|---------------|--------------|----------------|--------------|---------------|
| Material type | Synthetic polymer | Natural wood | Cellulose-based | Inorganic glass | Ferrous metal |
| Durability | Medium | Low–Medium | Low | High | Very high |
| Use case | General, reusable | Craft, traditional | Disposable, low-cost | Precision, lab | Industrial, heavy-duty |
## How to choose
- Is the product made of plastic? → 3923.40
- Is it wooden and used for crafts or textiles? → 4421.99
- Is it paper-based and meant for single use? → 4822
- Is it glass, clear, and used in sensitive environments? → 7017.90
- Is it metal, heavy, and built for industrial strength? → 7326.90
## Overlaps & pitfalls
A product could be made of wood but coated with plastic (e.g., a wooden core with plastic rim), making it ambiguous. Similarly, paperboard spools may have metal inserts. **No option takes priority by default**—choose based on the product’s MAIN material and primary function. If unsure, prioritize the dominant structural material