## Common ground
Both options refer to metal components used in construction, but neither is a greenhouse framework—these are specific fasteners or materials.
## Options at a glance
**7308.90 – Iron/steel with copper heads**
- **Defining trait:** Made of iron or steel with copper heads; primarily used as fastening hardware.
- **Typical examples:** Copper-headed nails, steel tacks for wood or metal joints.
- **Best fit when:** The product is a small fastener used to assemble greenhouse panels or frames.
**7907.00 – Made of zinc**
- **Defining trait:** Entirely made of zinc; typically used for corrosion-resistant coatings or sacrificial components.
- **Typical examples:** Zinc-coated screws, galvanized nails, zinc-plated washers.
- **Best fit when:** The product is a corrosion-resistant fastener, often used in outdoor or humid environments like greenhouses.
## Key differences
| Feature | 7308.90 – Iron/steel with copper heads | 7907.00 – Made of zinc |
|-----------------------|----------------------------------------|-------------------------------|
| Base material | Iron/steel | Zinc |
| Primary function | Fastening | Corrosion protection |
| Common use in greenhouses | Structural assembly | Weather-resistant components |
## How to choose
- Is the product primarily made of iron or steel with a copper head? → 7308.90
- Is it made entirely of zinc (e.g., galvanized, coated)? → 7907.00
## Overlaps & pitfalls
A zinc-coated iron nail might fit both if not clearly defined—zinc is the coating, not the base. If the product is a fastener with a zinc layer, use **7907.00**. If it has a copper head on steel, use **7308.90**. The key is material composition: base vs. coating. Do not assume "zinc" means full zinc content—check if it's plated or solid