Can we use those little rubber shapes that go on by suction on glasses in order to distinguish one from the other on Shabbos?
Answer:
There is no problem with using “suction shapes” on glasses on Shabbos. Suction hooks must not be used on walls, because they become part of the wall, and this is prohibited on account of boneh, building (Shemiras Shabbos Kehilchasah 23:39; footnote 121). However, there is no problem of using suction operated ‘shapes’ for glasses and other movable items.
