5-Stars! Excellent set of flash cards for beginning students, or for those who might need a refresher course in musical theory. The cards, themselves, are durable and not paper thin, and have a laminated coating which is a great feature for younger learners. I shopped around, a bit, before deciding on purchasing this set. What caused me to, ultimately, go with this company and series, was how the cards were color coded by category, and that Solfège terms, for auditory musical comprehension, was included.Including a photo of the piano section indicating the featured key that is being highlighted is a great feature. This will insure that students will get all pertinent information for sight comprehension and auditory learning at a quick glance. You can tell that this company took to the time to talk with musicians, musical teachers, students, and parents, etc. to get feedback to determine what features should be included.I wish I’d had this set when I first was learning music [30+ years ago]. I purchased the first set to help refresh my memory [I’m starting to study piano, again, after many years.]. I’ll purchase another set, soon, for a young cousin who’s starting to study piano.NOTE: I’m not paid for this endorsement and have not been compensated for my review. This set is worth the price, as you’ll, definitely, get your money’s worth. I would, highly, recommend.