I'm guessing this is a siliconE jacket, not a silicon jacket?
Silicon without the 'e' is a metal. It's one of the main things that computer chips are made of, and is a component of sand, glass, etc. "Silicon valley" is where all the tech companies are.
Silicone with the 'e' is a rubbery substance used in cookware, caulk, breast implants, and "skin" type electronics cases. "Silicone valley" would be a completely different valley, probably much closer to Hollywood...