I take my Hydroflasks with me literally everywhere I go; the climbing gym, camping, shooting, class... you name it. I have both the coffee mug and the water bottle and on most days I have both of them with me at once. No lie, they keep my drinks hot or cold for literally twelve hours. My sister used to make tea in her coffee mug the night before because it would stay that hot over night. Everyone you know probably already has one of these bad boys, you probably have one yourself! But on the off chance you don't, invest NOW!