Technical specifications: Material: stainless steel. Dimensions: 68 x 31 x 16 mm. Colour: silver. Quantity: 2 double window stoppers Functions: To prevent children from opening the window and accidentally falling. Safety device to stop children's dangerous fingers. Keep the air fresh and ventilated. Ideal for use in private homes, dormitories, hospitals, schools , universities and offices. Notes: 1. Since measurements are taken by hand, the sizes indicated may vary by 1-3 cm. Please make sure you do not mind before purchasing. 2. The color of the actual item may vary from the pictures, depending on your computer's display and brightness settings. Please take the actual object as the standard. Thanks!. 3. Please note that you have measured the wheel size before purchasing.