It's a pad about the size of a note card, called "Geckskin". It has both rigid and flexible components, and can easily be removed from surfaces such as glass, wood, drywall, various plastics, and metal. No trace is left and it can be reused.
Not long ago, I told readers of "Crape Murder" - the damage that can be done by severely cutting limbs off healthy Crape Myrtles. This needless practice happens every spring, for no reason at all except that it creates busy-work for the "cutter".
Well I've been watching Crape Myrtles all over north Texas. Out of the ones that were left alone, not one died that I know of. However, about a third of the Crape Myrtles that were severely "topped", died. In the worst case, 40% of them died at one institutional site, and the owner is now on the hook to pay for a bunch of new plants.