Aquatic Technology 5512WS1218E 12"x18" Orange/White No Breath Holding Warning Sign is printed on .040 mil Styrene Plastic, and is designed to prevent patrons from holding their breath, hyperventilating or doing extended underwater swimming. Our Warning signs indicate a potentially hazardous situation which, if not avoided, could result in death or serious injury. This sign is lightweight, durable and weatherproof for indoor or outdoor use.