The suction will work effectively on smooth, clean surfaces such as plastic high chair trays, tabletops, countertops, glass, and stone. For optimal performance, it's essential that both the suction base and the surface it's attached to are clean, dry, and free of any soap film. This ensures a strong, lasting grip.However, please note that some high chairs and surfaces, especially those that are textured, rough, unfinished, or damaged, may not support long-lasting suction. This includes popular highchair tray models like Stokke Tripp Trapp, Clikk, Bugaboo Giraffe, and Nuna Zaaz, which have a textured surface.For these specific models, we offer a special solution: a suction sticker designed to overcome the common issue of bowls not sticking properly to textured surfaces. Simply apply the suction sticker to your highchair tray, and you'll enjoy the reliable suction performance of our products on these otherwise challenging surfaces.Remember, for the best suction results, ensure that the surface and the suction base are both clean and dry before use.