Update it’s not 75” long, it’s short on the bed which is highly annoying. It measures 71”…. 

It’s measuring about 9” 24 hours later, the instructions say to wait at least 72 hours, so we’ll see. I did take a quick lay on it, and it does feel comfortable. A bit softer than I was wanting but our old mattress was super soft and ruining my hips and back, this will definitely help.