| Surface Treatment | Feature |
| Chemical Treatment | minimize the chance of humid-storage staining forms a dark gray surface discoloration on the surface |
| retain the bright metallic luster for a long period | |
| Oil | minimize the tendency for humid-storage stain |
| Chemical Treatment and Oil | The chemical treatment provides very good protection against humid-storage staining, while the oil provides lubricity for operations. |
| Dry | must be transported and stored with special precautions to preserve low-humidity conditions. |
| Anti-finger print | minimize the chance of humid-storage staining forms a dark gray surface discoloration on the surface |
