Feature - The main body consists of a ventilation belt with 3 transverse bars at the inner side, an outer strong rlastic belt, and a special designed pressure mat - The adjustable and double-pressure elastic belt can stabilize the lower trunk and reduce pain - The design with 3 transverse bars provides effective limitation  to the excessive trunk rotation - The special designed pressure mat gives user a comfortable support excessive trunk extension, and it does not affect normal trunk movement during exercise Applications - Lumbar disorder - Low back pain - Low back protect for athletes in sports involving trunk extension, such as badminton,volleyball and javelin SIZE : Measure around the waist S   23 - 28 (inch)    58.4 - 71.1  (cm) M   28 - 33 (inch)   71.1 - 83.8   (cm) L   33 - 38 (inch)    83.8 - 96.5   (cm) XL 38 - 43 (inch)    96.5 - 109.2 (cm) What's in the Box : 1piece x 3D support with pad