Musical Glasses

Imagine touring Europe for 16 days with a bus full of high school band geeks. It was awesome being one of the high schoolers. But I imagine it was less awesome being one of the chaperones. Especially when we did things like play with the crystal glasses in a semi-formal Swiss restaurant. Hey! It's real! At least we were all musicians.

Some creative person decided to make life better for chaperones of musically-inclined, crystal-playing high schoolers (and those of us who would still play with their wine glasses on occasion, even into adulthood). Instead of guessing at pitches, these glasses conveniently mark how much water needs to be filled in order to get specific notes. The set of 12 glasses gives you a full octave.

My question: but in what key?

Found at Luna and Curious.