In space no one can hear you type!
This visor is one of 3 parts that make up the Astronaut keycap. Printed in transparent acrylic plastic it lets you see the eerie skull encased inside.
You can order the other 2 parts of the keycap here:
Please be aware that the "transparent acrylic plastic" material actually appears quite frosted at first. In order to get a completely transparent finish you will need to polish the visor. I used some Tamiya polishing compound and a cotton bud.