Lit, they glow with tiny pinpoints of light, like a starry sky. Unlit, their mirror surface reflects everything around it. Because they're cordless, you can put them anywhere: on a table, on a shelf, among plants or holiday greens. Timer switch shuts off after 4 hours. Takes 3 AA batteries. Specify Small (about 5" diameter) or Large (8" diameter). The more, the merrier. Indoor use only.