OPTP SI-LOC® Support BeltTherapists prefer the SI LOC over other back braces and SI support belts because it stays in place. Patients prefer the comfort of the SI LOCs 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