Synthskin was a medical technology very similar to Human flesh. Synthdroids, Human replica droids, most prosthetic limbs, and General Grievous's gutsack were all covered in synthskin. It was very similar to synthflesh. DD-11A was also covered in synthskin. Synthskin seems to have been mistakenly (or colloquially) referred to as synthflesh while talking about prosthetic limbs.