Abstract: An attachable two-chamber breast prosthesis includes two volumes of silicone materials that have different degrees of softness. The prosthesis includes three pieces of polyurethane film (a front film, a middle film, and a rear film) that form a front chamber and rear chamber. The periphery of the front chamber is smaller than the periphery of the rear chamber. The rear chamber, which contains the firmer silicone material, extends to the peripheral edge of the prosthesis. The front chamber, which contains the softer silicone material, does not extend all the way to the peripheral edge along the upper region of the prosthesis. By increasing the thickness of the rear chamber along a boomerang-shaped region defined by the peripheries of the front and rear chambers, the firmer silicone material in the rear chamber provides the prosthesis with proper support and reduces the tendency of the prosthesis to pull away from the skin along the top edge of the prosthesis.