3606 - Ferrocerium and other pyrophoric alloys in all forms; articles of combustible materials as specified in note 2 to this chapter:

Chapter 36 of the Harmonized Tariff Schedule (HTS) encompasses a variety of materials and articles related to ignition and combustion, including explosives, pyrotechnic products, matches, and certain specialized alloys and combustible preparations. Heading 3606 specifically addresses ferrocerium and other pyrophoric alloys, along with articles manufactured from combustible materials that meet the criteria outlined in Note 2 to Chapter 36. Pyrophoric alloys are materials that ignite spontaneously when exposed to air, making them useful in applications requiring immediate ignition.

While other headings within Section VI deal with various chemical products, 3606 focuses on these specific ignition-related materials. For instance, it is distinct from headings covering general chemicals or more complex manufactured goods. Within Chapter 36 itself, 3606 is differentiated from categories like explosives (Chapter 3601-3604) or gunpowder and fireworks (Chapter 3605) by its emphasis on pyrophoric alloys and certain combustible preparations rather than explosive charges or pyrotechnic displays.

The subcategories under 3606 provide further detail on the forms and intended uses of these materials. Subheading 3606.10.00.00 specifically identifies liquid or liquefied-gas fuels packaged in containers designed for refilling cigarette lighters and similar devices, with a limited capacity. The remaining goods within this heading, such as other forms of ferrocerium, pyrophoric alloys not intended for lighter fuel, and other articles of combustible materials as defined by the chapter notes, fall under the residual category of "Other." This structure allows for precise classification based on both the material composition and its specific application or packaging.