A set of bionic legs was utilized by Huey Emmerich sometime after the Ground Zeroes Incident in 1975, made from Huey's own design.
The legs, powered by metallic archaea, were a product of the U.S. military's failed attempts to develop a powered exoskeleton, and were bolted directly into Huey's bones, enabling him to move them fluidly. However, as a result of the bolts, Huey's leg bones were filled with holes, and if the support parts were to be removed, the smallest amount of force would break his legs. Ocelot later exploited this, as well as Huey's fear, to get the information of where Skull Face was at by threatening to use corrosive Metallic Archaea on his legs.
After his betrayal of Militaires Sans Frontières to Skull Face, as well as his responsibility for the vocal cord parasite outbreak on Mother Base, was found out, rather than kill him, Venom Snake exiled Huey from Mother Base on a small raft that was too small to support his legs' weight, forcing him to dump the legs overboard to stay afloat.