Endorser ( Eng. Endorser - literally "voucher" or "witness") - a person using the products or services of another person under a contract involving the promotion / advertising of this second person and / or his products / services.
For example, it can be a musician using the instruments of any company, an athlete using the equipment or sportswear of any manufacturer, etc. At the same time, for example, a musician can indicate on his website which instrument he plays , and the manufacturer, in turn, may have a list of its endorsers with links to their sites. Thus, endorsement serves as a kind of mutual advertising.
In some cases, exclusive contracts are concluded. For example, guitarists Steve Wye and Joe Satriani are endorsers of Ibanez , and they are not allowed to publicly perform music on guitars of other companies.