"A month or two ago I purchased one of Contigo's Snap Seal Byron cups. I checked to be sure it did not leak and a week later bought another. A few weeks later I had the Snap Seal closed and the cup was in my lap, it tipped over and leaked very hot coffee all over my legs. I double checked and it was indeed closed. On looking the lid over it looked like the gasket was malformed. I wrote Contigo and asked for a new lid or gasket. They didn't reply. I wrote again and asked they contact me before close of business that day about this matter or I would write about it wherever I could. They never did reply. These cups are defective. If unattended they can spill hot liquid on anyone that handles them. It's an inferior product sold by an uncaring company. I'm using mine at the pistol range for targets. I mean they leak anyway right?"