Sodastream Crystal Indicator

thingiverse

This is an easy way to tell if you're using pure water or carbonated water in your Sodastream bottle. When you open the bottle, you'll see a wave symbol on the side - this means you've got pure water inside. But when you add some CO2, the indicator will flip and show six little bubbles instead of that wave. This is actually pretty handy because it makes it easy to read the "Sodastream" logo, which was facing the wrong way before. And if you want to make things even clearer, you can change the color at just the right spot - it's a clever design that helps prevent the cap from coming loose.