Designed with proprietary Distrodensity zones along its three-dimensional surface that are meant to simulate the feeling of a massage therapists handsWhen rolled through tight muscles, knots and kinks, it allows tissue to aerate, promoting oxygen and blood flood and boosts muscle repairThe compact size makes it travel friendlyHard, hollow coreWrapped in firm EVA foamCan support up to 500 lbs / 225 kg static load