Cura heat back pain max size are twice the size of regular cura heat back pain and cover a larger area of the lower back making them more suitable for people who desire warming relief over a larger area and may suffer from severe back pain cura heat back pain max size provides targeted temporary 12 hour warming relief from muscular and joint aches and pains just open the sachet and apply to the clothing underwear where the heat radiates through to the source of pain increasing circulatio