Is a Thera P memory foam mattress topper a good one? Why is it flat?

Intex Queen Foam Top Rising Comfort Raised Airbed Set
Rising Comfort Raised Airbed Set, Queen, Foam Top, (with 110-120 Volt Pump and Wireless Remote). May ship as brown or b… More >>

Homedics HMT-3F Soothing Comfort Mattress Topper- Full
High density memory foam gently supports entire bodyPremium Cool Core Memory FoamSuperior support300 thread count remova… More >>

I just bough this one from Linnens and More, there was also another one called Dream memory foam, but I figured the Thera P would be a better one. Coming out of the box its really flat. Is it suppose to expland within a while? How long? Or should I take it back?

Intex Queen Foam Top Rising Comfort Raised Airbed Set
Rising Comfort Raised Airbed Set, Queen, Foam Top, (with 110-120 Volt Pump and Wireless Remote). May ship as brown or b… More >>

Homedics HMT-3F Soothing Comfort Mattress Topper- Full
High density memory foam gently supports entire bodyPremium Cool Core Memory FoamSuperior support300 thread count remova… More >>

Disclaimer: This site is a paid affiliate of Amazon.com