AVAILABLE IN VARIOUS DIFFERENT SIZES, Powercall Sirens "Blacklite" decals are printed on 3M's top of the line 280 Reflective Black Material. Nobody can top it! The color "BLACK", or any other color that is printed on this material, shows when the light hit's it. When there is no light, the decal appears Black, as shown in the pictures These decals are made for your helmet (Hardhat size of 2"), window or any other smooth surface you wish to apply the decal on. We offer all of our decals in sizes from 2" (Hard hat size) up to 12". We also have options to customize our decals as well. Feel free to contact us for any questions or special requests. If you are interested in customizing this decal, please send us an email and we'll be glad to assist you. Each decal generally has a piece of CLEAR application tape over the top to assist you with installation. Please follow the instructions that come with your decal for easy installation.