## Common ground
All are laboratory components used to connect or condense gases/vapors in chemical setups.
## Options at a glance
**3926.90 – Plastic material**
- **Defining trait:** Made from chemically resistant plastic, ideal for low-temperature or non-corrosive applications.
- **Typical examples:** Polyethylene or PTFE adapters and condensers.
- **Best fit when:** Handling mild chemicals, needing lightweight or disposable parts.
**6903 – Refractory ceramic**
- **Defining trait:** Designed for high-temperature resistance and thermal stability under extreme conditions.
- **Typical examples:** Ceramic condensers in high-heat distillation setups.
- **Best fit when:** Operating above 800°C or with strong thermal cycling.
**6909.1X – Ceramic**
- **Defining trait:** General ceramic construction, often used for moderate heat and chemical resistance.
- **Typical examples:** Porcelain connectors or condenser parts in standard lab use.
- **Best fit when:** Moderate temperature and corrosion resistance needed, not extreme heat.
**7017 – Glass**
- **Defining trait:** Transparent, highly chemically inert, and suitable for precise visual monitoring.
- **Typical examples:** Glass adapters in distillation or reflux setups.
- **Best fit when:** Needing visibility, high purity, or standard lab conditions (up to ~500°C).
## Key differences
| Feature | 3926.90 (Plastic) | 6903 (Refractory ceramic) | 6909.1X (Ceramic) | 7017 (Glass) |
|---------------------|-------------------|----------------------------|-------------------|--------------|
| Max temperature | Low (~150°C) | Very high (>800°C) | Moderate (~600°C) | High (~500°C) |
| Chemical resistance | Good (mild) | Excellent | Good | Excellent |
| Visibility | No | No | No | Yes |
| Fragility | Low | High | High | Very high |
## How to choose
- Is the device used at temperatures over 500°C? → 6903
- Does it need to be transparent for visual monitoring? → 7017
- Is it exposed to strong acids/bases and needs high chemical resistance? → 7017 or 6909.1X
- Is it lightweight, disposable, or used with mild chemicals? → 3926.90
## Overlaps & pitfalls
- **Overlaps:** Glass (7017) and ceramic (6909.1X) both offer high chemical resistance; refractory ceramic (6903) is a subset of ceramic but for extreme heat.
- **Pitfall:** "Ceramic" (6909.1X) may include non-refractory types—ensure it’s not intended for high heat.
- **Priority note:** If the product's main function is thermal endurance, prioritize 6903; otherwise, use material suitability and application context to decide