NFPA Sign Kit (Placard, Digits & Symbols) By SmartSign | 12" Square Aluminum NFPA signs have four mounting holes for easy attachment Digits and symbols are included and are easy to attach to the NFPA sign blank Digits are self-aligning NFPA diamond, when measured from the top to bottom of the diamond, is actually 17" high (eg which is the same as the 12" square tilted by 45 degrees)