1. A method of making a prosthesis device comprising a flexible shell and a filling material, said method comprising:forming a plurality of first layers by coating a mold with a first silicone material, wherein the plurality of first layers has a first thickness and a first color;
forming one or more second layers by coating the plurality of first layers with a second silicone material, comprising:
a polydimethylsiloxane polymer having at least 10 mole percent of a pendant chemical group chosen from a diphenyl group, a methylphenyl group, a trifluoropropyl group, or a combination thereof;
a vinyldimethyl-terminated polydimethylsiloxane polymer; and
the one or more second layers providing a diffusion barrier to impede passage of the filling material through the shell, wherein the one or more second layers has a second thickness and a second color different from the first color of the plurality of first layers;
forming a plurality of third layers by coating the one or more second layers with the first silicone material, wherein the plurality of third layers has a third thickness greater than the second thickness and the same color as the first color of the plurality of first layers, and wherein a total thickness of the shell, comprising the first thickness, the second thickness, and the third thickness, ranges from 0.33 mm to 1.00 mm; and
verifying the presence of the one or more second layers in the shell by visual observation of the second color in the shell, the one or more second layers being visually distinguishable through the plurality of first layers without the use of an optical comparator, specialized equipment, or destructive tests.