Abstract: An elastic prophylactic device having an improved ductile metal barrier layer to prevent the transmission of virus, such as those causing AIDS or HERPES. The improved metal barrier is formed in such manner as to enable it to repeatedly expand and contract in concert with the elastic movements of the prophylactic device during its intended use, without fracture or breaking of the barrier metal layer. A number of processes for manufacturing the improved device are given, including initially stretching the elastic membrane of the device to the extent of its intended use, and vapor depositing a ductile metal in a thin, continuous coating onto the stretched membrane.