These hooks are designed for smooth surfaces like ceramic tile, glass, and plastic.
They are intended for use on smooth surfaces, but the packaging also mentions "irregularities," which might refer to the surface of the hook itself or a tolerance for minor imperfections on the application surface.
The image shows a set of six hooks, each with a distinctive yellow and white design.
They are likely used for hanging lightweight items in areas such as kitchens, bathrooms, or offices.