I bought a cap for $12, I tried heating it up to clean it and it popped in less than 2 seconds. Then I dropped it from 1 inch just to test it. And it cracked apart. I returned with in one hour and the guy said the best he can do is give me $5 store credit. He didn't want to refund or give me a better quality glass. If I knew it was cheap glass I wouldn't spend 12 on it.