King Serta iComfort Genius Mattress Comfort Rating: 3 - Firm Mattress Score Explained Mattress Height: 11 Type: MicroSupport Gel Memory Foam Mattress Orthopedically Supportive: Yes MicroSupport Gel: Unique open-cell structure of Sertas exclusive and breakthrough KoolComfort Memory Foam makes it significantly more breathable than traditional memory foam, promoting a cooler sleep surface