Decooo.be Anti-Collision Stickers to Prevent Persons or Birds Strikes on Window Glass/Choice of Colours Available (Set of 21 rounds - diameter: 3 in) (Translucent Frosted/Dusted) - Window decals Set of 21 rounds. Diameter: 3 in. Those round stickers can be used to prevent people window-shocks or bird strikes. Glass panels, verandah doors or bay windows can act like mirrors with the sun rays reflection. For this reason, we recommend to place those stickers on the exterior side of glass panels. The round stickers are coloured on both sides. So, colour of the stickers is visible both from the outside as well as from the inside. Guaranteed high quality materials with long-lasting adhesiveness (will not fall off over time, resistant to rain, freezing weather conditions and cleaning agents) and long-lasting colour (will not fade over time either). Possibility to combine several sets to mix different colours.