This is the next generation of the water diverter I made some time ago.
Check out my first version:
It will fit an aerator on a bathroom faucet with a diameter of 23.5mm.
There is no reason you could not scale this to fit another size faucet.
Smaller, lower profile so less space under your tap is used (important for low faucets)
Thinner walls as it didn't need to be as thick as the old one, smaller hole in diverter nozzle as this means the tap can be turned on less and gives better control of the water stream into your mouth.
I have paid attention to the interior as few nooks and crannies as possible for easier cleaning and less places for bacteria to build up.
I have had a chance to make a couple of these and use this new type, this is a much better thing to use on a daily basis.
Last note I have since printed it in clear PETG and I must say it gave it a nice crystal look (see last photo square cropped) hard to see the difference in the photos but PETG has demonstrated a good material to make this out of.
Medium (0.2mm layer height)
I printed this in ABS on medium resolution.
No Rafts or supports needed it took 27 minutes to print but you could slow the machine and get a better finish if you desire (your call)
Due to differences between machines I suggest stopping the print at around 25% completion and try it on the aerator if need be scale it up 1 or 2% to get a firm fit.
All being well set it going again and let it complete.
I only de-burred the inner edge that was in contact with the build platform.
I built this in Tinkercad.