The 45°+ Reverse Bevel Opening is created by cutting into the thicker matboard surface with the blade angled at 45°, thereby slanting the bevel under the matboard surface. The matboard core is not visible from the front. The Blade Depth must be above 16 in order for the CMC to prompt for the 45°+ Cartridge.
Full Definition: 45 Degree Plus Reverse Bevel Opening Definition |