## Common ground
All options refer to small spherical or bead-like particles (microspheres/minibeads) used in scientific, medical, or industrial applications.
## Options at a glance
**3926.90 – Plastic**
- **Defining trait:** Made from synthetic polymer materials like polystyrene or polyethylene.
- **Typical examples:** Lab-grade beads for immunoassays, cell sorting, or chromatography.
- **Best fit when:** Used in biological research, diagnostics, or as carriers in chemical reactions.
**6909.11,6914.10 – Porcelain/China**
- **Defining trait:** Made from high-fired, vitrified ceramic with a dense, non-porous surface.
- **Typical examples:** Wear-resistant beads for industrial polishing or high-temperature applications.
- **Best fit when:** Requires extreme hardness, thermal stability, or resistance to chemical corrosion.
**6909.11,6909.12,6914.90 – Ceramic**
- **Defining trait:** Made from non-metallic inorganic materials (e.g., alumina, zirconia), often sintered.
- **Typical examples:** High-performance beads for catalysis, abrasion-resistant coatings, or biomedical implants.
- **Best fit when:** Needs high strength, biocompatibility, or thermal/chemical resistance beyond standard porcelain.
**7018.20,7020.00 – Glass**
- **Defining trait:** Made from silica-based glass, often transparent and chemically inert.
- **Typical examples:** Fluorescent beads for microscopy, optical sensors, or calibration standards.
- **Best fit when:** Requires optical clarity, precise size control, or use in imaging/analytical instruments.
## Key differences
| Feature | Plastic | Porcelain/China | Ceramic | Glass |
|------------------|---------------|------------------|------------------|------------------|
| Material type | Polymer | Vitrified clay | Sintered oxide | Silica-based |
| Transparency | Variable | Opaque | Opaque | Transparent |
| Thermal resistance | Low to medium | High | Very high | High (but brittle) |
| Common use | Lab assays | Industrial wear | Biomedical, catalysis | Imaging, sensors |
## How to choose
- Is the material primarily a synthetic polymer? → 3926.90
- Is it opaque and used in high-heat or abrasive environments? → 6909.11,6914.10
- Is it made of advanced oxides (e.g., alumina) for strength/biocompatibility? → 6909.11,6909.12,6914.90
- Is it transparent and used in optical or imaging applications? → 7018.20,7020.00
## Overlaps & pitfalls
- Porcelain/China (6909.11,6914.10) is a subset of ceramic; some products may fall under both. Use the more specific code if known.
- Glass and plastic can both be used in lab settings—prioritize material type: glass for optical needs, plastic for cost or flexibility.
- If unsure, base choice on the **primary function**: e.g., imaging → glass; cell binding → plastic; wear resistance → ceramic