Not sure, but you could get a sapphire crystal from these people. www.krysworks-store.com I had replaced my real vintage plastic Rolex sub crystal with a sapphire one and it looks good and no more scrathes.
Finally received the 1:1 copy after 3 months. Like Watchmaker said, it is exactly what he has delivered. The only fault is that the bezel is not tightly attached and can easily come off. The ss strap is not hollow linked. However, the cyclop magnification is identical to the real thing. Overall, it is one of the best replica that I had ever purchased. I need not show photos because they are identical to the ones watchmaker had shown.