Trigger point grid xthe grid x foam roller is trigger points firmest foam roller it was created to break through the bodys toughest tightest trouble spots for relief from intense aches and pains dense tissue needs a firmer grid foam roller to release and relieve aches and pains the grid x can be used to release the calves quadriceps hamstrings back and lats features three dimensional surface allows tissue to aerate while you roll promoting the flow of blood and oxygenthe nutrients nee