Ultra Water Saving Device - Shower Flow Restrictor

I use one of these in both of my showers to conserver water. I included a 0.5/0.75/1/1.5/2/2.5mm orifice water saver disc as different people have different wants and water pressure (mine is very high and I use the 0.75mm size where I get ~0.8gpm out of a 2.5gpm shower head. The 2mm is about 1.5gpm and the 2.5mm is ~2-2.25gpm all at full force so you can turn down the faucets to lower it even more).