## Common ground
All options are fasteners or metal fittings, specifically forged cramps or dogs used to secure or join materials.
## Options at a glance
**7317.00 – Made of iron or steel**
- **Defining trait:** Primary material is iron or steel; most common for heavy-duty applications.
- **Typical examples:** Steel cramps for concrete formwork, steel dog clamps in construction.
- **Best fit when:** Used in structural, industrial, or high-load environments requiring strength and durability.
**7415.10 – Nails, tacks, drawing pins, staples... with heads of copper**
- **Defining trait:** Head made of copper; body may be iron/steel but head is copper (not the whole item).
- **Typical examples:** Copper-headed nails for roofing or decorative work.
- **Best fit when:** The product has a copper head, even if the shaft is steel—common in specialized or aesthetic applications.
**7415.10 – Made of copper**
- **Defining trait:** Entirely made of copper; distinct from copper-headed items.
- **Typical examples:** Copper cramps for marine or chemical environments (corrosion resistance).
- **Best fit when:** The entire fastener is copper, used where corrosion resistance or conductivity matters.
**7508.90 – Made of nickel**
- **Defining trait:** Entirely made of nickel; high corrosion and heat resistance.
- **Typical examples:** Nickel cramps in chemical plants or aerospace.
- **Best fit when:** Requires extreme durability in harsh environments (e.g., acid, high temp).
**7616.10 – Made of aluminium**
- **Defining trait:** Lightweight and corrosion-resistant; made entirely of aluminum.
- **Typical examples:** Aluminum cramps for aircraft or outdoor structures.
- **Best fit when:** Weight is critical or used in corrosive but non-extreme environments.
**7907.00 – Made of zinc**
- **Defining trait:** Entirely made of zinc; often used for galvanizing or sacrificial protection.
- **Typical examples:** Zinc-coated cramps (though pure zinc is rare).
- **Best fit when:** The product is primarily zinc, though this is uncommon for structural cramps.
## Key differences
| Option | Material | Head Type | Corrosion Resistance | Weight |
|-------|----------|-----------|------------------------|--------|
| 7317.00 | Iron/Steel | N/A | Low to moderate | Heavy |
| 7415.10 (copper head) | Steel body, copper head | Copper head | Moderate | Medium |
| 7415.10 (copper) | Copper | Full | High | Light |
| 7508.90 | Nickel | N/A | Very high | Medium |
| 7616.10 | Aluminum | N/A | High | Light |
| 7907.00 | Zinc | N/A | Moderate (sacrificial) | Light |
## How to choose
- Is the entire item made of steel or iron? → 7317.00
- Does it have a copper head but steel body? → 7415.10 (copper head)
- Is the entire item made of copper? → 7415.10 (made of copper)
- Is it entirely nickel? → 7508.90
- Is it entirely aluminum? → 7616.10
- Is it entirely zinc? → 7907.00
## Overlaps & pitfalls
- **Overlap:** The two 7415.10 entries are easily confused—only the head material differs. Clarify if the *entire* item is copper or just the head.
- **Pitfall:** Zinc cramps (7907.00) are rare; most zinc items are coated, not solid. If it’s galvanized steel, use 7317.00.
- **Priority rule:** Use the *primary material* of the fastener as the defining trait. If unsure, prioritize full material over partial (e.g., copper head ≠ copper item)