Hi, a friend of mine sent me a picture of a Cartier Diabolo rollerball pen someone gave him, asking me if the pen was possibly a fake. I told him I'd never seen a Diabolo like this before, and the refill doesn't even bear a brand name, likely a third party refill. However, I couldn't be 100% sure this is not a genuine item. Comparing it with the pic I took from Rakuten, you can see the difference.
I would appreciate it if you can give me some advice on whether it's a fake.