The term SERTA RIVAL is referring to the two leading mattress companies in the United States, Serta and Sealy. Both companies have been around for over a century and are known for their high-quality mattresses. Serta is the largest mattress manufacturer in the US, while Sealy is the second largest. Both companies offer a wide range of mattresses, from traditional innerspring to memory foam and hybrid models. They also both offer a variety of price points, making them popular choices for consumers.