Zicbol One way window film provides with you a daytime privacy, blocks out the most of UV rays and isolates the heat to create a comfortable space for you, static cling design make it easy to install and remove, and not hurt your window glass. Some useful tips: 1. Make sure you have peel off the protective film before you install the window film, this is important. 2. The window film only works on smooth, clean and flat glass doors and windows. 3. Please remember to leave 2-3 mm gap from the edge of the glass to the film to avoid falling or curling. 4. Spray enough water onto the window and the back side of the film during the installation progress, the more, the better.