## Common ground
All options refer to T-shaped supports, which are structural components used to reinforce or connect parts in assemblies.
## Options at a glance
**3926.90 – Made of plastic material**
- **Defining trait:** Constructed primarily from synthetic polymer materials like polyethylene or PVC.
- **Typical examples:** Plastic T-brackets for shelving, PVC pipe fittings, 3D-printed structural supports.
- **Best fit when:** The support is lightweight, non-conductive, and used in environments where corrosion resistance or low cost matters.
**8302.4X – Made of base metal**
- **Defining trait:** Fabricated from ferrous or non-ferrous metals such as steel, aluminum, or iron.
- **Typical examples:** Steel T-clamps for machinery, aluminum framing connectors, metal brackets in construction.
- **Best fit when:** High strength, load-bearing capacity, or durability under harsh conditions is required.
## Key differences
| Feature | 3926.90 (Plastic) | 8302.4X (Base Metal) |
|--------------------|--------------------------|----------------------------|
| Material | Synthetic polymer | Iron, steel, aluminum |
| Strength & Durability | Lower | High |
| Corrosion Resistance | Good | Varies (e.g., stainless better) |
| Weight | Light | Heavy |
## How to choose
- Is the support made of plastic or rubber? → 3926.90
- Does it contain iron, steel, aluminum, or other base metals? → 8302.4X
## Overlaps & pitfalls
A T-shaped support could technically be made from metal with a plastic coating, but the primary material determines classification. If unsure, prioritize the **main structural material**—not surface treatment. The term "base metal" includes iron and steel, so even coated or alloyed metals fall under 8302.4X if they are not purely non-metallic