It is made from a special, printable transparant plastic sheets: you can buy them from an office supply store, big department store or a special hobby store.
I printed a light yellow colour on one of those sheets so the visor is semi-transparant.
Printable plastic transparancies can be a bit expensive though: sometimes you can also buy transparant plastic sheets that are already coloured, and then you can simply trace the "papercraft" parts with a pen on the plastic sheet and cut them out like that and you will have a similar effect. ;o)
I'm sure they have it somewhere in your country, but sometimes if you live in a small town it's difficult to find the right shop...
There or online webshops where you can buy hobby and craft supplies, but sometimes it's very expensive... (
Like I said, it doesn't necessarily have to be special, printable paper sheets if the part only has one colour: then you can use any plastic sheet that has the right colour, like packaging plastic from other things you bought.
Sometimes if you look around a bit and use your imagination, you can find lots of things that you can use, or maybe you will be able to find a hobby shop near where you live, or in a big city you sometimes go to.
And of course, there are many other paper models you can find that don't require special sheets of paper or plastic of course, so I'm sure you can keep busy in the meatime! ;o)