I just changed out my core from a Medium firmness to xtra stiff on my side of the bed. It’s just over a year old.
36"x83.5"x6" .
I’m in Phoenix, would prefer to keep it local if possible. The core is from Arizona Premium Mattress Company. If interested in turning it into a 6" mattress, APMC will put a cover on it and add pieces to make it a full twin or twin XL size for $139 additional. Would make a good kids mattress.
PM if interested
Thank you