I tried sleeping on the mattress in the store and confirmed that it was firm with a lot of coils, so there was no bottoming out or side-to-side rocking, and it was comfortable. I recommend it for people with back pain. If it feels too firm, I think you can adjust it by putting something on top. I bought a bed with a slightly higher height that can be stored under the bed, so this thin mattress is convenient for getting in and out of bed easily. On the negative side, the content of the email from Nitori was quite complicated, and I had a lot of trouble trying to check the delivery status of the product, or even though I had set it to “phone contact required before product arrival”, I didn't receive a phone call, etc., which was very annoying. It was stated that there were cases where it would not be possible to make a phone call, but if it's a service that can't be provided, it's a nuisance, so it's better not to have it in the first place. In fact, I bought it for my parents, who live in a facility far from my home, and I was planning to move it to their room after making a phone call. However, it was delivered to the facility at 9am, and the facility staff had to move it to their room, which was a nuisance. The delivery company should be able to make a phone call, so it's bad that Nitori doesn't instruct them to do so.