1. Back Support Belt: The lumbar support features 4 memory aluminum struts, which are four times stiffer than conventional PP strips, along with 2 steel springs along the waist to deliver robust support and significantly alleviate back pain. It provides rapid relief for back pain, arthritis, muscle pain, herniated discs, sciatica, and more. Please measure your waist circumference at the belly button. S: fits 23.6' 29.5'. M: fits 29.5' 39.4'. L: fits 37.4' 45.3'. XL: fits 45.3' 49.2'. XXL: fits 51.2' 57.1'. 2. 3D Lumbar Support Cushion: The back support belt is designed with a specially contoured shape that snugly conforms to your back. Its deep lumbar support offers massage, promotes blood circulation, supports the waist, relieves back pain, reduces muscle fatigue, and provides maximum protection for the back and spine, even when lifting heavy objects. It significantly improves spinal curvature and reduces pressure on the spine structure. 3. Improve Poor Sitting Posture and PostureMost people in the workplace experience heavy strain on their waist. For employees, fitness enthusiasts, supermarket cashiers, and luggage handlers, prolonged overloading of the waist leads to lumbar muscle strain and a hunched back. This not only diminishes your posture but also significantly impacts your health. The advanced back support belt effectively alleviates various back issues, corrects poor sitting posture, and helps you achieve a more upright and confident stance. 4. Comfortable and Breathable: The back strap is crafted from elastic 4way stretch material using 3D knitting technology with varying compression levels, ensuring an fit, breathability, and comfort. The inner layer is made of plush velvet fabric, offering a silky, babyskinlike feel, making it for wearing under clothing.