A male bra, also known as a compression bra, support vest, or bro, is a bra worn by men with enlarged breasts. They're typically designed to flatten and conceal the breasts, rather than to lift and support them, but they only differ superficially from female bras.
Men may choose to wear a bra for one of three reasons. When a man has enlarged breast tissue due to obesity and/or gynecomastia, he may choose to wear a brassiere to provide support and/or to flatten his chest. On the other hand, some men wear more feminine bras for cross-dressing. And others wear them for sexual purposes, as a way to demonstrate submission to their partner.