1、 Reusable anti-collision stickers to prevent bird strikes: static and non-stick vinyl stickers-each deterrent is coated with ultraviolet rays-glass window and door decorations can remind birds. Prevent birds from flying into the windows.2、 Package content: 20 window butterflies. Each butterfly averages 5 x 6.7 inches. Suitable for use on glass panels, patio doors or bay windows.3、 Beautiful window stickers: These realistic butterflies can be seen on both sides. They not only prevent birds from flying on your windows, but they can also add beauty to your home. Can also be used as a stained glass hanger.4、 UV-resistant, these stickers are made of the highest quality vinyl and will not fade under direct sunlight. One should place them at least 4 inches apart for maximum efficiency.5、 Reusable: You can remove these window films at any time and reuse them year after year.