The use of trade marks and similar expressions in claims is not allowed as it does not guarantee that the product or feature referred to is not modified while maintaining its name during the term of the patent. They may be allowed exceptionally if their use is unavoidable and they are generally recognised as having a precise meaning.

With regard to the need to acknowledge trade marks as such in the description, see F‑II, 4.14. With regard to the effect of references to trade marks on sufficiency of disclosure (Art. 83), see F‑III, 7.