## Common ground
All options refer to book corners—small protective covers for book edges, typically used to prevent wear.
## Options at a glance
**3926.10 – Plastic material**
- **Defining trait:** Made primarily from plastic (e.g., polypropylene or PVC).
- **Typical examples:** Clear plastic corner protectors, flexible vinyl book guards.
- **Best fit when:** The product is lightweight, transparent or colored, and designed for easy application without adhesives.
**8305.90 – Base metal**
- ****Defining trait:** Made from a non-precious metal (e.g., steel, aluminum, brass).
- **Typical examples:** Metal book corner clips, decorative metal edge guards with rivets.
- **Best fit when:** The product is rigid, durable, and has a metallic appearance or feel—often used for high-end or archival books.
## Key differences
| Feature | 3926.10 (Plastic) | 8305.90 (Base Metal) |
|------------------|--------------------------|----------------------------|
| Material | Plastic | Non-precious metal |
| Flexibility | Flexible or semi-rigid | Rigid |
| Common use | Everyday protection | Premium or archival use |
## How to choose
- Is the book corner made of plastic (e.g., clear, flexible)? → 3926.10
- Does it feel heavy and metallic (e.g., steel or aluminum)? → 8305.90
## Overlaps & pitfalls
A product could be misclassified if it has a metal frame with plastic inserts—this would depend on the dominant material. If unsure, prioritize the **main structural material**. The term "base metal" includes common metals like steel and aluminum but excludes precious metals (gold, silver)