## Common ground
All options are spy holes—small openings for viewing, typically used in doors or walls.
## Options at a glance
**3925.90 – Made of plastic material**
- **Defining trait:** Constructed primarily from plastic, often lightweight and cost-effective.
- **Typical examples:** Plastic peepholes in residential apartment doors, molded plastic lens covers.
- **Best fit when:** The product is lightweight, non-metallic, and likely mass-produced for low-cost housing or temporary installations.
**8302.41 – Made of base metal**
- **Defining trait:** Constructed from metals like steel, brass, or iron, offering greater durability and security.
- **Typical examples:** Metal peepholes in high-security doors, commercial building entryways, armored door fittings.
- **Best fit when:** The product is robust, resistant to tampering, and used in settings requiring physical strength or long-term reliability.
## Key differences
| Feature | 3925.90 (Plastic) | 8302.41 (Base Metal) |
|---------------------|--------------------------|----------------------------|
| Material | Plastic | Steel, brass, iron |
| Durability | Lower | High |
| Security level | Basic | Enhanced |
| Common use case | Residential, low-cost | Commercial, high-security |
## How to choose
- Is the spy hole made of plastic? → 3925.90
- Is it made of metal (e.g., steel or brass)? → 8302.41
## Overlaps & pitfalls
A spy hole may include both plastic and metal parts (e.g., a metal frame with a plastic lens), but the primary material determines classification. If unclear, prioritize the **main structural material**. No option is vague—both are clearly defined by material type