Just put it on!! It vibrates to let you know when you slouch. KIWOTUKE It's not just a posture correction belt! It's a next-generation correction belt that alerts you to slouching with vibrations. The belt length is freely adjustable! It's also stretchy enough for use by children and adults. When your posture improves, your appearance also improves, and the burden on your body is reduced. KIWOTUKE has a built-in sensor that vibrates to alert you if you lean forward more than 25 degrees for 8 seconds. Instead of rigidly fixing your posture with a device, it gently reminds you when you accidentally slouch. Because you can be aware of the moment your posture collapses, it becomes training to maintain correct posture.