Vinyl is ideal for indoor and sheltered outdoor marking needs. 4-mil thick printed matte surface. Permanent acrylic adhesive backing. Plastic is appropriate for everyday medium-duty marking needs. .055" thick with good impact resistance and surface image with non-glare finish. Aluminum withstands splashes and wash-downs indoor and out; providing strength of metal, without rusting. Text is printed on ridged .040" aluminum sheet, protected by UV poly over laminate. Meets OSHA 29 CFR 1910.145 and ANSI Z535.