Actually I am aware of enough of the construction issues and is WHY I would even bother asking if anyone else is into this type of construction. Yes. This is for aquarium maintenance. The 445 nm e/w G2 lens unit I have is sometimes used several times a day. Focus to within a foot inside the aquarium gives very good results. Killing critters reflecting off a large dental-like mirror 18" into the tanks leaves something to be desired. It does work but takes much longer and both sets of batteries when they fully charged.
Active marine aquarium owners with large systems have enough invested in their systems that there is little room for screwing around. People with smaller systems, not so much. Now that I have several weeks experience with this handheld laser, I now consider it a start. Definitely not a final solution. Considering that this device is dangerous in its own right, alternatives solutions are less power but water proof in some way (fiber optic??) or more power and external.
I have not researched this at all of recent, but I had development experience long ago with fiber optics for local area networks. All about wavelength compatibility, but in my minds eye at the moment would be a wall plug in air cooled laser module with a fiber cable coming off. Close in focus, a couple of inches or so, should allow for lower power lasers to be used. I don't really need to write my name in card board a foot away ... just sayin'