Photoluminescent Valve Tags are made of matte plastic with a photoluminescent core enabling the engraved text to glow-in-the-dark. Tags are engraved on 1 side and are 63 mil thick. Photoluminescent tags use IPI material that has received MEA certification from the NYC Department of Buildings (MEA-203-8-M). They comply with NYC Local Law 26. Tags glow brilliantly in a blackout. Tags are available in glow on red, glow on navy, glow on black, red on glow, green on glow, and black on glow color schemes.