Biker Skull Viking Decal Sticker can be used outdoors on vehicles, windows, boats or any other hard surface. Our vinyl decals hold up great in all of the elements and can last many years. In extreme uses we offer "3M Clear Guard". This is a clear vinyl that adheres over the decal and is unnoticeable. It gives extra protection against abrasion and UV light. To include this please select the "3M Clear Guard box" when purchasing. An extra charge will be added. Go to "About Our Decals" for more information.