Serta's Modern Series is a collection of thinner profile, all foam mattresses with cooling features, all at incredible prices. Available in three comfort levels to offer the right feel for all users. Serta® PureComfort Gel Foam provides cushionin and cooling along with the Serta® CoolWickTM Breathable Cover, keeping you cool and comfortable all night. The plush edition also has CoolTwist® Gel Memory Foam for additional pressure relief. The Plush "Luxury" is a good mattress for a side or back sleeper.