Diamond Multimedia introduced the Rio PMP300, one of the first commercially successful portable MP3 players, in 1998.
The Rio PMP300 was released in September 1998 and used flash memory to store compressed digital music. Its standard capacity was 32 megabytes, enough for roughly an hour of music depending on encoding settings. A 64-megabyte version was also offered.
The device became historically important because the Recording Industry Association of America sued Diamond Multimedia, arguing that the player violated copyright law. In 1999, a United States appeals court ruled that the Rio was a lawful personal-use recording device. The decision helped clear a legal path for portable digital music players.
The Rio PMP300 predates Apple’s iPod, which arrived in 2001. It was not the first MP3 player ever made, but it was among the earliest widely noticed consumer products in this category. That distinction is why the Rio is often discussed as a bridge between downloaded music and the later iPod era.