These work so well and hold up so much better than the GUM brand (which my dentist recommended). I was so frustrated as I was throwing them away every few days if they even lasted that long. And, yes, I had the right size.I decided to try some less pricey options. These come in just a small plastic bag so not as wasteful as their expensive counterparts. It appears the colors actually denote different sizes. Not sure why it is not advertised that way. I find it a positive thing and like the different sizes. Blue and Orange seem to be the biggest and green and purple the smallest. I feel so good about this purchase!