Surfacing Level Marker Labels (specify English or Spanish): (2.5" x 2.5") allow maintenance people, supervisors, and users to quickly and easily check the support posts for the proper amount of loose fill surfacing depth.
If the surfacing is below the marker, it's time to fluff it up or add more surfacing (IF condition of surfacing allows). See CPSC Sections 2.4.2.2(4) and 4.3.