Calf Implants are normally made from medical grade silicone, a pliable,  yet firm, solid piece of silicone.  Solid Silicone is generally well-tolerated by the body and has the capacity to be formed into various shapes.Normally these blocks of silicone can be carved to custom fit an individual for implantation.  The medical grade silicone is non-reactive and considered non toxic and an excellent choice for augmentation in these areas.