Bests & Worsts Reviews from Amazon

I have four of these mugs. Pros: - Keeps coffee hot for a very long time when sealed. - Doesn't leak. - Durable. - Carabiner makes it easy to clip onto backpack. Cons: - A little inconvenient to clean. - Nissan unresponsive about replacement parts. Tips: Make sure the lid is screwed down snugly, but not too tightly. You want to form a complete seal to prevent leaks and retain heat, but the seal gets tighter as the contents cool and shrink. Don't fill past the raised metal fill-line on the inside of the mug. If you overfill the mug, some liquid will be pushed up into the threads when you screw the lid down, and you won't notice until you tip the mug. (It's easier to see the line if you fill it beneath an overhead light.) If you think your mug leaks, you've probably overfilled it. If you fill it just right, you don't even have to stir your coffee. Just add your sugar, cream, ketchup, or whatever you put in there, seal the lid, and shake the mug to mix it. (I've never been able to do this with any other mug). When you wash the mug, remember to remove and wash the silicone rubber o-ring. The lid is hollow and can be pried apart with a spoon for cleaning if some liquid seeps inside. If you wash the mug in the dishwasher (Nissan recommends against this), remove the plastic base before (or after) washing to remove the water that collects in there. If you lose the gasket (or cut it on a knife in the dishwasher like I did), I've found these to be suitable inexpensive replacements after a lot of hunting around: 228 Silicone Rubber O-Ring 70A Durometer, Burnt Orange, 2-1/4" ID x 2-1/2" OD x 1/8" W, by Small Parts Inc. ASIN:B000FMYTD2 Part Number ORS-228-10 Silicone O-Ring, 70A Durometer, Red