8506.40 - Silver oxide:

This HTS category, 8506.40, specifically covers primary cells and primary batteries utilizing silver oxide as their active cathode material. These types of batteries are characterized by their high energy density and stable voltage output, making them suitable for applications requiring long service life and reliable performance. Examples include button cells and coin cells commonly found in watches, calculators, small electronic devices, and medical equipment.

Distinguishing this category from its siblings, 8506.10 (manganese dioxide), 8506.30 (mercuric oxide), 8506.50 (lithium), and 8506.60 (air-zinc) lies solely in the chemical composition of the cathode material. While all are primary cells and batteries, their operational characteristics, energy density, voltage, and cost vary significantly based on the specific active materials employed.

The subcategories within 8506.40 further refine the classification based on physical dimensions. 8506.40.10 applies to silver oxide primary cells and batteries with an external volume not exceeding 300 cubic centimeters, typically encompassing smaller battery formats. Category 8506.40.50.00, "Other," serves as a residual for silver oxide primary cells and batteries that do not meet the volume criteria of the preceding subcategory, generally including larger or less common form factors.