Luke Skywalker's mechanical arm was covered by synthskin.
Synthskin, alternatively known as synthetic skin, was an artificial covering made of polymer that mimicked the appearance of real flesh. Medical personnel could utilize synthskin patches to help close wounds on organic beings.
Following the Separatist invasion of Fucallpa, Roman Herbane had a synthskin prosthesis replace his lost limb, but he was more saddened by the passing of his secretary, Li-Tan, than the loss of his limb. The remaining vital organs of General Grievous were shielded by synthskin. Maia, a Partisan, obtained a pair of synthskin gloves after winning a wager against her fellow fighter, Codo.
A substance similar to synth-skin was Nu-skin.