I bought these after being impressed with the commercial on them. Received them yesterday and tried 3 of them right away on leftovers i had in the 'fridge. All three of them came unsealed within 15 min.I thought i would do a little experiment and try them overnight with different types of bowls(plastic, metal, glass) Not one of them remained sealed by morning. To further agitate me, they only refund product cost, not shipping and handling. product $10, s&h $15.90. I am steamed. read full review »