A high guard ceiling type. Grade 1 is designed for maximum security and is ideal for prisons, detention centers, and other high security zones. Grade 4 is designed for light security and is ideal for airport washrooms, classrooms, light detention centers, and other light security zones. Security access panel with special tool is available for both grades. Tested as per ASTM F2322-2012 standards for maximum Grade 1 criteria & tested for load bearing capacity.