This is good quality tac. Cost effective as compared to blu-tac, and works similarly or even better. I have used it for a variety of purposes - like putting up small paintings on a laminated wall, posters/ pictures , I even use it at the end of a stick to fish out things fallen into narrow places where hands can’t go etc.
Obviously the heavier the item the more qty you have to use otherwise it will fall off after a few hours/ days. I use at least 4-5 squares for my small paintings ( 6 by 4 inch) on a rough laminated surface. Also smoother surfaces will have less sticking power than rough so use more for smooth surfaces.