Therapists prefer the si-loc over other back braces and Si support belts because it stays in place. Patients prefer the comfort of the si-loc?s lightweight, breathable fabric and non-bulky design that conceals easily under clothes. si-loc offers relief from low back pain and back spasms, along with referred pain in the hip, pelvis or sciatic pain extending down the leg. its Patented, tapered design is wider at the innominates for even pressure distribution, making it comfortable to wear for long periods while keeping steady, supportive pressure on the Si joint. wide, medical-grade, non-slip pads prevent the si-loc from sliding while dual hook-and-loop closures allow user to adjust the anti-slip buckle to where it is most comfortable. developed by the iaom-us; patented. sizing information: measure the pelvic circumference at a level 1? above the most superior aspect of the greater trochanters.