Anti-collision bird stickers decal prevent birds and people strikes. Made of PVC, doing a good job of keeping your furry flying friends from crashing into the picture windows! Easy to install, post to the window/door. Peel it off, stick it on, done! We recommend to put decals to outside of the window, but in case, if can not reach the dangerous outside of window, you can stick it inside, the effect may be influence a bit. Reduce your feathered friends accidents and prevents breakage. It is a long-lasting self-adhesive backing that fit for smooth surface glass doors and windows.