## Common ground
All are laboratory dishes used for holding, mixing, or heating substances in scientific settings.
## Options at a glance
**3926.90 – Plastic material**
- **Defining trait:** Made from synthetic polymer (e.g., polypropylene), lightweight and disposable.
- **Typical examples:** Petri dishes, centrifuge tubes, sample containers.
- **Best fit when:** Single-use, chemical resistance, low cost, or need for transparency.
**6903 – Refractory ceramic**
- **Defining trait:** High heat resistance; withstands extreme temperatures without degrading.
- **Typical examples:** Crucibles, furnace dishes, high-temp reaction vessels.
- **Best fit when:** Used in kilns, flame heating, or high-temperature reactions.
**6909.1X – Ceramic**
- **Defining trait:** General ceramic material; less heat-resistant than refractory types but durable and chemically stable.
- **Typical examples:** Beakers, evaporating dishes, general lab ware.
- **Best fit when:** Moderate heat use, chemical resistance, reusable lab work.
**7017 – Glass**
- **Defining trait:** Transparent, chemically inert, and heat-resistant (e.g., borosilicate glass).
- **Typical examples:** Petri dishes, beakers, reaction flasks.
- **Best fit when:** Need visibility, precision, or resistance to most chemicals and moderate heat.
## Key differences
| Feature | 3926.90 (Plastic) | 6903 (Refractory ceramic) | 6909.1X (Ceramic) | 7017 (Glass) |
|--------------------|-------------------|----------------------------|------------------|--------------|
| Heat resistance | Low | Very high | Moderate | High |
| Transparency | Varies | No | No | Yes |
| Reusability | Often disposable | High | High | High |
| Chemical resistance| Good (varies) | Excellent | Good | Excellent |
## How to choose
- Is it transparent? → 7017
- Does it need to withstand high heat (e.g., flame or furnace)? → 6903
- Is it disposable and lightweight? → 3926.90
- Is it durable, non-transparent, and used for moderate heat/chemicals? → 6909.1X
## Overlaps & pitfalls
- A ceramic dish may be refractory (6903) or general (6909.1X); use of "refractory" is key.
- Glass and plastic can both be transparent; heat resistance distinguishes them.
- If a product is reusable, heat-resistant, and non-transparent, it could fit 6903 or 6909.1X—choose based on actual thermal tolerance.
- No priority rule given; use the **main function** (e.g., high-temp use vs. visibility) to decide