Brighten up your birthday party and add an element of fun with the Green Happy Birthday Circle Glow Shape! Each circle shaped Green Happy Birthday glow shape measures approximately 3" in diameter and has a self-adhesive backing that allows it to be attached to almost any surface. To activate your Green Happy Birthday Circle Glow Shape simply locate the ampoule in the center, press firmly until it snaps, then shake to disperse the glow product. Please note the glow feature in the Green Happy Birthday Circle Glow Shape is intended for one-time use only. The happy birthday glow shapes are sold by the piece.