“Although I appreciate Marc's work on the 1521, I have several issues with the blue bezel. The lack of contrast between the index marks and the blue background of the ring when in the dark. After just a few minutes in the dark, the 2 blend together and make reading the bezel almost impossible. The bezel insert glows well enough, it's really the fact that the glow permeates the blue ink/dye of the ring. If the glow could be blocked better, increasing the contrast, this would be a worthy upgrade. This is something I have not experienced on other crystal inserts.
The second issue I suspect is a byproduct of the multilayers needed to make an illuminated crystal insert. When mounted in the bezel, the insert sits proud of the bezel shoulders. It's not a huge amount, perhaps 1/2 mm, but because if the sharp edge of the crystal insert, it might be susceptible to chipping or breakage if it gets dinged. Without further development on the bezel insert, I just can't recommend this upgrade.”