Glow Worm™ phosphorescent powders can be added to Smooth-On liquid plastics, rubbers and foams to create castings that glow in the dark after being charged with light. You can choose from 8 different powder colors. What sets Glow Worm™ powders apart from other glow-in-the-dark powders? Used as directed and after being light charged as recommended, castings made with Glow Worm™ powders will glow in the dark at least 10 times longer than other glow powders. Glow Worm™ castings are used for Halloween theming displays, home hobby projects, aquariums, store displays, as well as industrial marking, municipal safety applications and more.