SAFE ON SURFACES - Use hook on clean, smooth surfaces such as windows, doors, glass, tile, acrylic, and porcelain, Not for wood, non-glass or rough surfaces. Surface should be above 40 Fahrenheit when applied. Slightly wet surface for best results. POWERFUL SUCTION - USA-made suction cup offers a powerful yet gentle hold that grips smooth surfaces like no other. REMOVES EASILY: without leaving scratch marks or damage behind when hook is removed. EXTRA LARGE HOOK - Our large hook makes it a breeze to hang large items such as wreaths, signs, and other big holiday decorations up to 10 pounds in weight INDOOR & OUTDOOR USE - For use indoors and out; its easy keeping your house looking festive all holiday season long. Directions: Firmly press suction cup against surface then attach hook into loop.