This is a watch face that snaps on to the F-91W to make a functional watch that looks like the out-of-production Casio F-100.
For the Aliens Crew watch, you can buy the double watch face here:
https://www.shapeways.com/product/TBJ3A4SZN/functional-ripley-double-watch-face
And the orange surround here:
https://www.shapeways.com/product/46WYK9WJW/functional-ripley-watch-surround