Rol, Thanks for a review and a useful input. Bed mattress in Thailand is usually very firmed. My mattress is on the firmed side but it's no way near as hard as many other typical Thai mattress. Most of my guests had no problem with it and I even already have a returned guests. So I guess it's a matter of reference. Anyway, thanks for raising this issue up. I'll add this to the room description to make sure guest with bad back problem is aware of this. In the near future, I'd also add a soft topper. So there will be an option for every one.