I wish I could give 3.5 stars.  While I'm still getting used to this mattress (and it is indeed firm and I like it, don't get me wrong), just know that the twin size, because of the way that it's made, is actually a bit smaller than most twin beds all the way around.  I would have purchased an extra long twin mattress had I known.  I also paid an extra delivery fee to have it delivered to my door "inside", and because of Covid-19, the awesome delivery guy couldn't take my old mattress.  I totally understand that, but some of that extra fee should be refunded to me in my opinion, because that service was not completely provided.  It's been two weeks and no one from customer service has gotten back to me regarding my request.  So while I wait, 3 (and a half) stars shall remain.