## Common ground
All options are low pressure cylinders made from different metallic or plastic materials.
## Options at a glance
**3925.10 – Plastic material**
- **Defining trait:** Made from non-metallic, typically lightweight and corrosion-resistant plastic.
- **Typical examples:** Air tanks for scuba diving (non-metal), gas storage for camping stoves.
- **Best fit when:** Weight, cost, or chemical resistance are priorities; not for high-pressure use.
**7311.00 – Iron or steel**
- **Defining trait:** Made from ferrous metal, offering high strength and durability.
- **Typical examples:** Industrial air tanks, compressed gas cylinders in factories.
- **Best fit when:** High mechanical strength and long-term reliability are needed.
**7419 – Copper**
- **Defining trait:** Conductive, corrosion-resistant, and used where purity or thermal properties matter.
- **Typical examples:** Refrigerant lines, laboratory gas systems, HVAC components.
- **Best fit when:** Non-reactivity with certain gases or need for heat transfer.
**7508.90 – Nickel**
- **Defining trait:** Highly corrosion-resistant and thermally stable; used in harsh environments.
- **Typical examples:** Chemical processing equipment, aerospace gas systems.
- **Best fit when:** Exposure to corrosive chemicals or extreme temperatures.
**7613.00 – Aluminium**
- **Defining trait:** Lightweight, corrosion-resistant, and recyclable.
- **Typical examples:** Portable gas cylinders, camping gear, medical oxygen tanks.
- **Best fit when:** Portability and resistance to rust are key.
**7806.00 – Lead**
- **Defining trait:** Dense, soft, and used only in niche applications due to toxicity.
- **Typical examples:** Rare; not typical for gas cylinders (may be misclassified).
- **Best fit when:** Specialized shielding or radiation containment (not standard for gas storage).
**7907.00 – Zinc**
- **Defining trait:** Used mainly in coatings or alloys; not common for standalone cylinders.
- **Typical examples:** Coated steel tanks, sacrificial anodes; not typical for pressure vessels.
- **Best fit when:** Part of a composite or protective layer (not primary cylinder material).
**8007.00 – Tin**
- **Defining trait:** Soft, corrosion-resistant, used in coatings or thin-walled containers.
- **Typical examples:** Food cans, decorative or low-pressure storage; not for gas pressure vessels.
- **Best fit when:** Non-metallic appearance or food-safe coating needed (not for pressurized gas).
**8101.99 – Tungsten**
- **Defining trait:** Extremely dense and strong, but very heavy and expensive.
- **Typical examples:** Rare; not used in standard low-pressure cylinders.
- **Best fit when:** Extreme durability or high density required (not practical for most uses).
**8104 – Magnesium**
- **Defining trait:** Lightest metal, highly flammable when powdered.
- **Typical examples:** Aerospace components; not safe for gas storage due to fire risk.
- **Best fit when:** Weight reduction in non-flammable applications (not suitable for gas cylinders).
## Key differences
| Material | Strength | Weight | Corrosion Resistance | Common Use Case |
|----------------|----------|--------|------------------------|----------------------------|
| Plastic | Low | Very low | High | Portable, low-pressure use |
| Steel | Very high| High | Moderate | Industrial, durable systems |
| Copper | Medium | Medium | High | Purity-sensitive applications |
| Nickel | High | Medium | Very high | Harsh chemical environments |
| Aluminium | Medium | Low | High | Portable, lightweight tanks |
| Lead | Low | Very high | Low | Shielding (not gas storage) |
| Zinc | Low | Medium | Moderate | Coatings, not vessels |
| Tin | Low | Medium | High | Food packaging, not pressure |
| Tungsten | Very high| Very high | Low | Extreme environments (rare) |
| Magnesium | Medium | Very low | Low (flammable) | Aerospace (not gas cylinders) |
## How to choose
1. Is the cylinder intended for portable or lightweight use? → 3925.10 or 7613.00
2. Does it need high strength and durability? → 7311.00
3. Is it used in a corrosive or chemical environment? → 7508.90 or 7419
4. Is it for medical, lab, or food-safe applications? → 7419 or 7613.00
## Overlaps & pitfalls
- Plastic (3925.10) and aluminium (7613.00) both suit portable use; choose based on pressure rating and durability needs.
- Copper, nickel, and aluminium are all corrosion-resistant but differ in strength and cost.
- Lead, zinc, tin, tungsten, and magnesium are poor choices for standard gas cylinders due to toxicity, flammability, or impracticality.
- **Do not assume any metal is suitable**—material choice depends on safety, pressure, environment, and regulations.
- If context is unclear, prioritize **main function**: for transportable gas storage → aluminium; for industrial use → steel