9021.90.40.40 - For hearing aids

This HTS classification covers dedicated parts and accessories specifically designed for use with hearing aids and pacemakers that stimulate heart muscles. This includes components such as earmolds, tubing, batteries, chargers, custom shells, and connecting wires. The primary function of these items is to enhance or maintain the operational effectiveness of the primary medical devices they are intended for.

This category is distinct from its sibling, 9021.90.40.80 "Other," which would encompass parts and accessories for other appliances listed under the broader heading 9021 but not specifically hearing aids or pacemakers. For instance, parts for artificial limbs or orthopedic braces would fall under the "Other" subheading, whereas components solely for auditory or cardiac stimulation devices are classified here.

As this is a leaf node, there are no further subcategories. Classification within 9021.90.40.40 is determined by the specific function and intended use of the part or accessory, which must be demonstrably linked to a hearing aid or a cardiac pacemaker for stimulating heart muscles, rather than a general-purpose item.