NFPA Aluminum Panel Holder
This aluminum NFPA panel holder measures 18 1/2" x 18 1/2" and can fit a 17" panel that slides in underneath the bar, so that the white border is hidden under the "lips" and only the colored boxes are able to be seen.
Holders attach to a post or stanchion with rivets or screws. 
Overall size: 18 1/2" x 18 1/2"

Price per NFPA Panel Holder