## Common ground
All options are reaction vessels—containers used to hold chemical reactions.
## Options at a glance
**3926.90 – Plastic**
- **Defining trait:** Made from plastic, offering lightweight, corrosion-resistant, and low-cost solutions.
- **Typical examples:** Polypropylene beakers, HDPE flasks, PET reaction tubes.
- **Best fit when:** Handling non-corrosive chemicals, needing disposability or low weight.
**6903 – Refractory ceramic**
- **Defining trait:** Made from heat-resistant ceramics designed for high-temperature and harsh chemical environments.
- **Typical examples:** Crucibles, furnace vessels, lab crucibles for melting metals.
- **Best fit when:** High-temperature reactions (e.g., >1000°C) or extreme chemical resistance needed.
**6909.1X – Ceramic**
- **Defining trait:** Made from general ceramic materials, often non-refractory; used for moderate heat and chemical resistance.
- **Typical examples:** Porcelain dishes, ceramic reaction pots, labware for mild heating.
- **Best fit when:** Moderate temperatures (up to ~600°C) and standard lab use.
**7017 – Glass**
- **Defining trait:** Made from glass, offering transparency, excellent chemical resistance, and inertness.
- **Typical examples:** Erlenmeyer flasks, round-bottom flasks, glass reactors.
- **Best fit when:** Need visibility of reaction progress, high purity, or resistance to most chemicals.
## Key differences
| Feature | Plastic (3926.90) | Refractory Ceramic (6903) | Ceramic (6909.1X) | Glass (7017) |
|---------------------|-------------------|----------------------------|--------------------|--------------|
| Max temperature | Low (~150°C) | Very high (>1000°C) | Moderate (~600°C) | Medium (~400°C) |
| Chemical resistance | Limited (some solvents degrade) | Excellent | Good | Excellent |
| Transparency | Opaque/Translucent| Opaque | Opaque | Transparent |
| Durability | Low (brittle when cold) | Very high | Moderate | High (but breakable) |
## How to choose
- Is the vessel used at very high temperatures (>1000°C)? → 6903
- Does it need to be transparent for visual monitoring? → 7017
- Is it for low-cost, disposable use or handling non-corrosive chemicals? → 3926.90
- Is it used at moderate heat and needs chemical resistance without transparency? → 6909.1X
## Overlaps & pitfalls
- **Overlap:** Some ceramics (e.g., porcelain) may fall under both 6903 and 6909.1X depending on refractoriness—clarify if high-temp use is intended.
- **Pitfall:** “Ceramic” in 6909.1X includes non-refractory types; don’t assume it’s heat-resistant like 6903.
- **Priority note:** Choose based on the vessel’s MAIN function—temperature, visibility, or chemical compatibility