## Common ground
All options are siphons categorized by their primary material.
## Options at a glance
**3922.90 – Plastic**
- **Defining trait:** Made from synthetic polymer (plastic), typically lightweight and corrosion-resistant.
- **Typical examples:** Household water transfer tubes, aquarium siphons.
- **Best fit when:** Durability in wet environments and low cost are priorities.
**4016.99 – Rubber**
- **Defining trait:** Flexible, elastic material often used for seals or flexible tubing in siphon systems.
- **Typical examples:** Rubber hose siphons, fuel transfer hoses.
- **Best fit when:** Flexibility and sealing ability are essential (e.g., uneven surfaces or moving parts).
**6910 – Ceramic**
- **Defining trait:** Fired clay; non-porous, heat-resistant, but brittle.
- **Typical examples:** Laboratory siphons, decorative or historical water features.
- **Best fit when:** High chemical resistance and aesthetic use are needed.
**7017 – Glass**
- **Defining trait:** Transparent, chemically inert, and breakable; allows visual monitoring of flow.
- **Typical examples:** Lab glassware siphons, precision fluid transfer systems.
- **Best fit when:** Visibility of fluid or chemical purity is critical.
## Key differences
| Feature | Plastic | Rubber | Ceramic | Glass |
|------------------|-------------|-------------|-------------|-------------|
| Flexibility | Rigid | Flexible | Rigid | Rigid |
| Transparency | Opaque/Translucent | Opaque | Opaque | Transparent |
| Durability | High | Moderate | Low (brittle) | Low (breaks) |
| Chemical resistance| Good | Good | Excellent | Excellent |
## How to choose
- Is the siphon used in a lab or for precise fluid monitoring? → 7017
- Does it need to be flexible or seal tightly on uneven surfaces? → 4016.99
- Is cost and general durability most important? → 3922.90
- Is appearance, heat resistance, or non-reactivity key? → 6910
## Overlaps & pitfalls
A siphon may combine materials (e.g., glass body with rubber seal), but the HS Code is based on the **primary material**. If unclear, prioritize the main structural component. No option is inherently superior—choose by function and environment