The r on the bottom of the glass can bottle represents the registered trademark (REGISTRED MARK)

1. A trademark that has been uniformly registered by the trademark authority. Since trademarks are intangible, registration is conducive to the publicity and credibility of ownership of rights and facilitates search and inquiry by others. In countries that implement the registration principle to confirm rights, mere use does not generate rights. In countries such as the United States that implement the use principle to confirm rights, registration does not create rights, but it can bring convenience in proof.

2. In my country, it means that a trademark approved and registered by the Trademark Office of the State Administration for Industry and Commerce is a "registered trademark", and the trademark registrant enjoys the exclusive right to use the trademark and is protected by law.