I was thinking of making something similar myself out of a camera cap, but then I saw a video of TeePee taking photos on monocleens. So I got the lens. I have to say that I was pleasantly surprised not only by the cool workmanship (even details like clicking into the camera like a classic lens), but especially by the actual shooting.

I love how lightweight it is, there's no focusing or aperture to deal with when shooting, and the resulting photos have a nice vintage style. I had it on holiday in Poland and I hardly used another lens for the whole week.