Review on 🥤 Premium Guardian Collection 18 oz Stainless Steel Tumbler by THERMOS - Sleek Slate Design by Sara White

First of all I would like to say that I am a big fan of Thermos and their products. I use this travel mug primarily for coffee and it keeps the coffee hot as advertised. The problem lies in the disk used to "seal" the cup and prevent it from spilling when the lid is closed. I've had a "spill" twice in the past, which I would compare to drinking a cold drink with ice, and the ice momentarily creates a dam preventing the drink from passing until the cup is lifted high enough will and the ice and drink will become free and splash. The difference between an ice dam and this mug is that hot coffee will burn. Every time I opened the mug, I found the locking disc floating in the coffee. I used to put it down to operator error. Today it happened again and now I understand why. The disc spins and "clicks" in place, but the "click" is barely noticeable and doesn't offer much resistance. The problem occurs when removing (unscrewing) the top with the lid open. The washer should touch the cup just enough to unscrew the washer enough that it no longer snaps into place. The cap can be removed without dropping the disc, but when the cap is screwed back on it is now loose. Sometimes I unscrew the cap until the threads engage so as not to mix up the threads, which can only make the problem worse. The next problem is getting the mug to work properly, which lowers your alertness. The disc levitates above the coffee until there is enough of it to move the disc down where the inner diameter of the cup is smaller. This is the moment when the disk catches on the sides, preventing the coffee from escaping, causing the cup to tip over until the full weight of the coffee is enough to overcome the disk, and the hot coffee over my mouth, mine face, my shirt and splashes In my case my laptop keyboard. . I was able to reproduce the problem easily: 1. Open the drinking cap2. Unscrew the top 3. With the cover open, screw the cover back on (worse, unscrew to activate the first thread)4. With the lid fully closed, tap the mug on a table or other surface5. Open the lid to find the disc is still in the circle. This problem is less likely to occur if you re-tighten the drive after removing the cover or reassemble the drive properly after the first cleaning. So for me it usually happens when I'm drinking my second cup. I had 2 different mugs from Thermos and each had a plastic retaining ring that was used to hold the pouring disk in place (two piece design). ). At first I liked this new design better as it was much "easier" to remove the disc. However, I think this design has not been fully thought through as it is now too "easy" to unlock the drive. I purchased this product based on my positive experience with the previous two old design mugs, however I cannot recommend this product until this issue is resolved. Remember you have been warned.