One of the elements that must be present in order to demonstrate that a mark is used in commerce, which is the fundamental requirement for the acquisition of rights in a mark. For a trademark to be "affixed" to goods, the mark should ideally be either placed on the goods themselves, or on their containers or attached tags or labels. The affixation requirement for goods may also be satisfied if the mark is prominently featured on a conspicuous display associated with the goods. If none of the above are practicable, the mark may be used on documents associated with the sale of the goods as a last resort. For services, a trademark is "affixed" if it is used in the sale or advertising of the services, as long as it is used in direct and explicit reference to the services provided.