## Common ground
All are containers used for holding, storing, or transporting small quantities of liquids or solids in laboratory settings.
## Options at a glance
**3926.90 – Plastic material**
- **Defining trait:** Made from synthetic polymers (e.g., polyethylene, polystyrene), often disposable and lightweight.
- **Typical examples:** Centrifuge tubes, PCR tubes, sample collection vials.
- **Best fit when:** Reusable or single-use applications requiring chemical resistance, low cost, or impact resistance.
**6903 – Refractory ceramic**
- **Defining trait:** Made from high-temperature-resistant ceramics (e.g., alumina), used in extreme thermal environments.
- **Typical examples:** Crucibles, high-temp reaction vessels, furnace components.
- **Best fit when:** Exposure to intense heat or corrosive molten materials.
**6909.1X – Ceramic**
- **Defining trait:** General ceramic material, typically non-refractory; less heat-resistant than refractory types.
- **Typical examples:** Porcelain labware, small storage containers, non-reactive vessels.
- **Best fit when:** Moderate use, chemical inertness needed, but not high heat or extreme conditions.
**7017 – Glass**
- **Defining trait:** Made from silica-based glass (e.g., borosilicate), transparent, chemically inert, and heat-resistant.
- **Typical examples:** Test tubes, beakers, graduated cylinders, culture dishes.
- **Best fit when:** Need for visibility, precision, or resistance to heat and chemicals.
## Key differences
| Feature | 3926.90 (Plastic) | 6903 (Refractory ceramic) | 6909.1X (Ceramic) | 7017 (Glass) |
|---------------------|-------------------|----------------------------|-------------------|--------------|
| Heat resistance | Low | Very high | Moderate | High |
| Transparency | Opaque/Translucent| Opaque | Opaque | Transparent |
| Chemical resistance | Good | Excellent | Good | Excellent |
| Reusability | Often single-use | High | Medium | High |
## How to choose
- Is the tube used at high temperatures (>500°C)? → 6903
- Does it need to be transparent for observation? → 7017
- Is it disposable and lightweight (e.g., for PCR or blood samples)? → 3926.90
- Is it non-transparent, chemically inert, but not for high heat? → 6909.1X
## Overlaps & pitfalls
- A glass tube may also be used at high temperatures—still fits 7017 unless specifically refractory.
- Ceramic tubes (6909.1X) can sometimes withstand moderate heat, but not as well as refractory types (6903).
- If a product is both plastic and reusable, it still belongs to 3926.90 unless otherwise specified.
- **Priority:** Choose based on the material’s primary function—heat resistance, transparency, or chemical stability