The Harmony Ortho is a specialized Ortho Range. The Ortho Range beds are firmer then the Harmony due to the smaller density of the pocket springs. The flex support foam provides more stability for your back and hips. This bed is ideal for people who suffer from chronic back pain and other back- related problems. 1000 of extra-firm L–Springs are layered into the core of this mattress, providing you with a more supportive feel.