The Serta Perfect Sleeper Merriam Luxury Firm mattress combines Serta’s Cool Action™ Gel Memory Foam  with a premium all-foam support system-Featuring Serta Balanced Support Foam. This foam combines gentle cushioning with extra support, for a firmer comfort. This mattress also features Serta’s Foam Core with Ultimate Edge® foam encasement- This durable foam core ensures outstanding support for your body. The high-density foam sides strengthen the mattress edges to reduce roll-off.