13" pac bamboo plus. i've done some research on foam mattresses both on interrnet and actual mattress stores before i purchased my item from bedinabox. 

           i'll tell you bedinabox co. gives you all the details you can possibly ask about in their FAQS. and their research studies you can read.   call them and you actually get a real person , if they dont answer when you call , leave your number and they will call you, thats what happened to me and thats unusual now a days. the staff at bedinabox was excellent to work with. 

 when my 125lb. package arrived i couldnt believe...