19 CFR § 10.2020 - Accessories, spare parts, or tools.
(a) General. Accessories, spare parts, or tools that are delivered with a good and that form part of the good's standard accessories, spare parts, or tools will be treated as originating goods if the good is an originating good, and will be disregarded in determining whether all the non-originating materials used in the production of the good undergo an applicable change in tariff classification specified in General Note 35, HTSUS, provided that:
(1) The accessories, spare parts, or tools are classified with, and not invoiced separately from, the good, regardless of whether they are specified or separately identified in the invoice for the good; and
(b) Regional value content. If the good is subject to a regional value content requirement, the value of the accessories, spare parts, or tools is taken into account as originating or non-originating materials, as the case may be, in calculating the regional value content of the good under § 10.2015.