Exit Sign Is Edge Lit The Eco-Clear 2003 by Active Safety Corp. is an edge-lit, photoluminescent, glow-in-the-dark exit sign. It uses strontium aluminate crystals as its power source, absorbing ambient light during normal operations and using the stored energy to designate exit routes at night and in an emergency. It has an operating life of about 25 years. (801) 265-9943 / www.activesafety.com