Use for pain stemming from kyphosis, osteoporosis, bad posture, hyperextension, spinal compression fractures, spinal stenosis, mechanical back pain, and more. Through the high strength of the horse line and two mobile pulleys with the role of easy to stretch the thin line and play a role in tightening the waist, generate abdominal compression that relieves pressure multiplies your force by five. According to the curve of human lumbar spine, Supports your back and holds the spine straight, protecting you from movements that could derail your recovery from a mid- or low-back injury. Made from breathable materials with soft padding. Fastener and quick-release buckles make it easy to put on, take off, or adjust the brace. Size S is suitable for waist 66-76cm (25.98-29.92inch); M is suitable for waist 77-89cm (30.31-34.25inch); L is suitable for waist 88-98cm (34.64-38.58inch); XL is suitable for waist 99-109cm ( 38.97-42.91inch). Using a soft / flexible tape measure, find the circumference of your waist at its narrowest point.