I purchased the firm, California King mattress on 716. I allowed it to blow up, which didn’t take no more than a few hours. I waited until the next day to sleep on it to be sure it settled correctly. I kid you not, this mattress is as described. It’s definitely firm, it’s 14 inches, and it did not hurt my sciatic back. My husband and I are large people and this mattress has not even dented with us both being on it. Our other mattress is just memory foam and we both suffered from back and shoulder pain on that, but this is a hybrid that works for our bodies. I would suggest you try it but be sure to put the mattress on the correct side (white side up) like the picture shows.