Pricey, but they are a very good mailer. Cannot be xray through them or water damage to contents if you tape over where it seals. Worth a try if you are looking for a sturdy mailer.Came quick and is what I needed!Well-made thermal bubble envelope. Did the job. Will use again. Thanks!The adhesive strip needs a lot of reinforcement but the envelopes do what they’re intended to. I used these to ship body butter in over the summer. It didn’t keep it frozen, but the envelopes plus some tweaks to the recipe kept it from melting.Make sure you measure your items before purchase or else you make have an issue. I had to adjust mine a bit to accommodate the jar. It worked but a larger size would have been better. Take the time - it’ll be worth it. The product is amazing though once sealed.I shipped products to customers and felt the items were protected!Lo recomiendoI bought these to use in conjunction with dry cool packs, so that I could send chocolate and food to my daughter in college ; as I live in Hawaii and it goes all the way to Pennsylvania! It totally did the trick . I didn’t even wait for the weather to cool down a bit - that would take forever here in Hawaii! It had to make it transiting several days. She said when she opened it that the ice packs were still slightly cool! Unbelievable! Score! Best necessity for mailing care packages with food in them !!!!!next I will be sending home baked cookies and banana bread !the image showed black envelopes, but the description says silver. guess which one i thought i was buying?