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! Full UV Reflective Coverage Design: Decals are fully coated with UV-reflective material—visible as normal colors to humans but as bright warning signals to birds, helping prevent collisions with glass. It is a long-lasting self-adhesive backing that fit for smooth surface glass doors and windows. Easy 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.