The length of the waist and the crossing back straps can be adjusted with Velcro. I've only worn it for a few hours. Below is an automatically generated description: [Product Overview] This posture corrector is designed to improve back posture. It's especially ideal for those who suffer from slouching due to long hours of desk work or smartphone use. [Material and Design] Made of lightweight and breathable mesh material, providing a comfortable fit. The cross design provides firm support. [Size and Fit] Size is M, and it has adjustable straps, allowing it to fit your body shape. - Color: Black - Size: M - Country of Manufacture: China - Type: Posture Corrector Thank you for viewing.