The first thing I noticed when I unwrapped my Tervis 15 oz tumbler was the fact that it is made of plastic. I know that the product description does not mention glass (or plastic for that matter), but for the nearly fifteen dollars I paid for it, I certainly was expecting glass. This was quite a disappointment. I will cover this subject further in a later paragraph of the review. The tumbler looks thick in the picture, but it is not made of solid plastic. Instead it is made of an outer plastic piece that is either glued or heat sealed into an inner piece with air in between. If I was a betting man, I would have to bet on it being glued rather than heat sealed. I say this, because unfortunately my particular mug has some white residue in part of the seal in the air buffer area near the handle, resulting in a 3/4 inch x 3/32 inch cloudy translucent strip which speaks of shoddy craftsmanship. The tumbler also came with two visible scratches on its inside that I have not been able to buff out. It's unlikely that the factory sent the item with them and it is more likely that they were introduced by Moshya Home Furnishings, the Amazon seller that the product originated from (you save thirty cents by going with a seller with an 82% review rating and you get scratches in return). Where the two pieces are joined near the rim (the bonding circle), the area does not appear very "clean" all around the circumference of the tumbler. This is difficult to see in the pictures. In other words, the bonding circle is somewhat uneven along its edge giving me a visual of a hot glue gun being used by a person at some factory. I will be hopeful and assume that this was an automated process, however. It may be of interest that the concentric circles that are visible in the picture are etched into the "inner cup," on the air bubble side (i.e., between the two plastic pieces), so as not to be felt if one rubs a finger along the inner portion of the tumbler. Update to previous paragraph: It's a bit hard to believe, but after doing some research I discovered that Tervis actually uses ultrasonic sound waves to "weld" the inner cup to the outer cup, so no worries of glue or heat welding residue apply. The tumbler itself was packaged with two labels on it. One on its side and one on its bottom. I was able to peel off the side one relatively easily, but the bottom one which was a paper label left its sticky glue behind. I don't know if it came that way from the factory or was a sticker placed there by one of Amazon's third party sellers, which sold me the mug. It was a royal pain to get the glue residue off. Being no stranger to this sort of nonsense, I took 99% isopropyl alcohol and went into a rubbing frenzy with a paper towel dipped in said alcohol. It took me about 4-5 minutes to finally get the glue (goo) off of the bottom of the tumbler. Update to previous paragraph: After doing some research, I discovered that Tervis recommends the use of mayonnaise to remove the glue goo. Just apply mayonnaise, wait five mins and then rub off. Peanut butter seems to work well too. It seems that the natural oils/fats in these products help disolve the glue and make it easier to remove without damaging the tumbler. Who would have thunk it? By the way, under no circumstances should products like Goo-Be-Gone be used, as they will mar the plastic surface. Here are some details regarding the tumbler's measurements. It weighs 8.4984 oz (240.93 g). It can hold 17 oz of water at its peak and up to 18.10 oz of pure water before spilling over. It's base outer diameter measures 2 5/8", while the outer diameter of its rim measures 3 29/32". My four fingers can comfortably slip inside its handle. With a vertical spacing of 3 3/16", I am fairly certain that even fairly large fingers would not have difficulty, but you can measure the width of your hand if you want to be certain. Let's move on to the plastic from which it is made. It is not clear what plastic material is used to make the tumbler. It does not have the usual plastic recycle number that is present on many plastic products. With the ever growing scare of BPA (bisphenol A) leeching from plastic products, one is left to wonder. The saving grace is that the manufacturer does explicitly state that it is microwave and dishwasher safe, hopefully nullifying this concern. I will still avoid using it in the microwave (or washing it in the dishwasher), but at least feel somewhat comfortable with leaving hot liquids such as coffee in the mug for prolonged periods of time without fear of leaching. Manufacturer guidance with regard to usage at high temperatures can go a long way to alleviate the ever present fear of how a particular plastic product will react when subjected to heat (and the dishwasher). Update to previous paragraph: After some research, I have discovered that the tumbler is made from Eastman Tritan, which is a copolyester (recycle code 7) that is genuinely safe and has no BPA or estrogenic/androgenic activity. You can find much information about the product safety of this plastic at the Eastman web site. As an aside, I just noticed that Evenflo is using Tritan for their new line of Comfi baby bottles:Evenflo BPA Free Purely Comfi 9 oz Bottle, 3-Pack . To test the item's resistance to heat, I filled it with fourteen ounces of water and subjected it to a five minute microwave test in a 1350 W microwave. The water began to boil at approximately the two minute point and continued to boil for another three minutes. Right as the water started boiling (i.e., at two minutes), I heard a fairly loud pop. It sounded like the tumbler had suffered structural failure. Fortunately, it did not and came out unscathed, so in the final analysis, I am not sure what the cause of the pop was. It sounded like a loud single plastic cracking sound, but after much examination I can detect no damage to the tumbler. On the positive side, immediately after this boiling torture test, the handle was cool enough to hold and the outside of the tumbler, although somewhat hot was still holdable for some 2-3 seconds, before one noticed that it was in fact a bit hot to hold. Keep in mind that the content at the time was water close to its boiling point. I am not a big fan of containers that are too hot to hold whether by handle or by the container itself. I feel that at normal tea/coffee temperatures, this tumbler does a good job of isolating the hot liquid inside from one's fingers. Finally, let me give you my rating and summarize. I gave the product three stars. I know this is less than most other purchasers rated the product, so let me give you the details behind my thought process. First of all, I subtracted one star for the fact that this nearly fifteen dollar product is plastic. When one can purchase a solid thick glassPyrex Prepware 2-Cup Measuring Cup, Clear with Red Measurements for just over seven bucks, this plastic mug's price does seem rather excessive. I also subtracted one more star for the shoddy bonding site between the inner and outer cups that form the tumbler. To me, this is definitely an eye sore and deserves the subtraction of a full star from the rating. Other than these two concerns, it does seem like a fine product and hence the remaining three stars stay intact. Let me end the review by stating that functionally the tumbler works well, is comfortable to hold and use, manages to stay upright when pushed from the side even while empty and looks nice from a reasonable distance. Thank you for reading my review.
