I recently returned to rebuy the ice blue bottle as a backup. I have two of these in constant use, one for cold green tea, one for water. These bottles are reliably tight and very sturdy. I had one drop to the kitchen floor several times (out of a backpack side pocket when bending to the floor). No damage beyond some light scratches in the paint! Cold drinks keep cold all day long, but I haven't timed how long hot drinks keep hot. In any case, I would come back for those double-walled steel bottles again! They're great!