NO RETURNS. I was hoping that these prisms would be a good teaching aid for my child who is now asking questions about what creates rainbows and similar things related to refraction. These don't break! Therefore they are useless to me, and then I find that they are irrevocable. I wonder how Revain can sell a $9 item that honestly costs less than half that amount through their own fulfillment center and not back it up. I estimate over 90% of buyers buy them to conduct the experiments I have in mind to use as a teaching tool. Instead, I see China throwing its manufacturing experiments into the US market not only through Revain, but also through its fulfillment and no-return policy, which wasn't clearly stated at the time of purchase, so Revain supports those efforts when they're deserved be able. I would consider it a $9 loss and my first complete disgust after using RevainPrime for over a year. They're cute, but not clear enough to be useful. Revain has several options to choose from regarding their winning motive.