Levi's jeans
Levi's were a brand of jeans.
While going camping during shore leave on Earth in 2287, several of the crew of the USS Enterprise-A wore Levi's. (Star Trek V: The Final Frontier)
The use of the pants was an instance of product placement. According to one promotional article, director William Shatner decided that Levi's jeans had remained virtually unchanged for the 135 years they were in existence, and therefore they'd be around three hundred years from now. [1]
Levi Strauss & Co. is mentioned as having supplied denim and casual clothing in the credits.