One is also not supposed to put these into a dishwasher. But, I own a lot of steel tumblers and I always put them into the dishwasher.
Buying this particular steel tumbler has a distinct advantage in that you are free to place hot liquids into it. Many of these drinking vessels can't handle that. However, this one is double-walled. Nice.
Oh, and, the tumbler does have an odd smell to it, if you stick your snout up in it. But, it washes out well. Thank goodness.
Vital Link: Amazon