A binder is a garment worn to flatten the breasts and create a less stereo-typically feminine appearance. They are commonly worn by trans men and gender nonconforming individuals as a means to present a more masculine or gender-neutral appearance.
More About Binder
Individuals wishing to conceal their breasts often attempt to flatten them. However, many of the ways available to do this (ace bandages, tape) can be detrimental to one's health. Binders are designed exclusively for this use. It should be noted that binders do come with their own health concerns and should be worn no more than 8-10 hours per day.
It is important to note that body dysphoria can be extremely traumatic and binders, available online and through specialty retailers, can be financially inaccessible. This may lead people to turn to unhealthy binding methods. Campaigns like TransActive's In A Bind work to increase binder accessibility.
