If you've ever wondered what your TRV900 looks like inside, this gives you an idea. Remko R Van Ginneken contributed these images of the TRV900, taken with a medical X-Ray machine, to the TRV900 mailing list (reproduced by permission). In the second image, you can see mounting screws and some internal lens elements of the TRV900, as well as a UV filter mounted on the lens hood.