HOW IT WORKS? ** If your profession is related to continuous work in an inconvenient pose for the spinal column, the load on it can be mitigated with the help of an elastic body posture corrector. The curative effect of the Tonus Elast corrector is provided by the "effect of memorising" the correct position of the spinal column. ** When wearing the Tonus Elast corrector for the first few days, a feeling of discomfort appears - it is normal and natural, as correction of the wrong routine of the spinal column muscles is going on. ** It is also important, that wearing the corrector "does not switch off" the work of your own muscles and does not disturb the normal rhythm of your heart. In two-three months of regularly wearing the product, a stereotype of the correct body posture is worked out. ** For the elderly, the corrector will help in supporting the physically correct position of the spinal column and will relieve the tension of the back muscles. SIZE: You should measure your chest directly under the breast: Small (68-78 cm), Medium (79-88 cm), Large (89-99 cm), X-Large (100-106 cm).