We use about five Post-it Notes a day. We’d use more if they didn’t crumble at sight of moisture, rain, or coffee rings, however. Well, it looks like we’re about to use more, as Post-it Extreme Notes are the Post-it Notes designed for poor conditions. The 3″ x 3″ sticky notes are water resistant and durable, making them the Post-it Notes perfect for outdoor use or for those who have a tendency to spill their coffee. Able to stay put on a variety of different surfaces, 3M Post-it Extreme Notes perform in both hot and cold environments, and they peel off without leaving a trace. Choose from classic colors like yellow, orange, or green.