2 ½” (38mm) is UL listed and can be labeled upon request Available with the Identify® recessed area for color coding, bar coding and/or identification markings Exceeds NFPA 1961 and UL standard performance requirements Maintenance free; just wipe down and return to service Highly resistant to fuels, chemicals, oils, heat & environmental pollutants. Impervious to molds, mildew & other airborne organisms