7321.81 - For gas fuel or for both gas and other fuels:

This HTS category, 7321.81, specifically encompasses nonelectric domestic appliances designed for use with gas fuel, or a combination of gas and other fuels. The core characteristic of items classified here is their reliance on gaseous fuel for operation, distinguishing them from appliances that utilize solely liquid or solid fuels. This includes a broad range of household cooking and warming devices.

Crucially, 7321.81 differs from its sibling categories by its fuel type. Appliances classified under 7321.82 are exclusively for liquid fuel, while 7321.89 covers those for solid fuel and other unspecified fuel types. Therefore, the defining criterion for this node is the explicit requirement or primary function of utilizing gas as the energy source.

Within 7321.81, further subdivision exists to refine classification based on portability. The subcategory 7321.81.10.00 is designated for portable gas-fueled appliances, suggesting smaller, easily movable units. Conversely, 7321.81.50.00 encompasses all other gas-fueled appliances that are not portable, typically referring to larger, stationary domestic cooking and warming units.