We got this for my daughters extra long twin mattress when she was waking up with aches and pains. It solved the problem big time! Shes six, and was still climbing in bed with us basically every night. Shes so comfortable and sleeps so soundly that she is staying in her bed consistently every night for the first time in her life. This is definitely thick and you do sink down into it as an adult, I think it would be too soft for me. But if you like a really plush sleeping experience, this is great! And it is very breathable, too - no sweatiness in the morning, even in Florida.