I have a pretty soft mattress (memory foam). I like it, but it does create situations where I start feeling sweating at night (especially with a nice comfy warm conforter). I thought I would have to deal with this forever, but this topper essentially fixed the situation for me. The topper creates a nice soft top, but it allows the additional airflow needed to keep everything nice and cool.

The 2 inch size is perfect and it fits most of my sheets and fitted sheets just fine. 

Highly recommended!