The model "Byron" keeps warm longer than the model "Contigo West Loop", even if it is more convenient to drink (and different button closure system).
The "Byron" requires to press hard on the tab to open up, to press hard for the tab down to close. You practically have two hands, even if done with one hand. The closing is not automatic.
The "Contigo West Loop" requires pressing lightly on the button to open, and when released, the opening closes. More practical driving for example. But it keeps the heat as long. This certainly is the size of the upper cap (to integrate the mechanism) which transmits heat.
