these photoluminescent super-glow anti-slip dots absorb and store energy from ambient light. They are immediately visible in a sudden black-out or underneath smoke. Intended for indoor applications; ideal in office and light industrial environments, away from forklift traffic. These durable dots are made from polycarbonate, a sturdier material than vinyl, and have a rough surface for very good skid prevention. Self-adhesive. Important: install on wet-cleaned, dust-free, dry smooth floor surfaces.