Glow in the Dark Heart Decals Wall Stickers Removable Wall Art, 6" x 8" Available in two sizes. Luminescent designs are easy to apply and turn your room into a magical space, day or night. The subtle daytime hue is powered up in just a few minutes from artificial or sunlight. Then, turn the lights out and enjoy the show for up to 8 hours! They last indefinitely inside, and are suitable for outdoor use for up to a year. Removable but not reusable once removed Self Adhesive. Application instructions included with every order. These decals will not adhere to walls painted with eco-friendly (low/no VOC) paint, paints that have a stain-blocker or mildew resistant additive in them that makes it very difficult for the vinyl to stick.