Resembles Metal Imperial Officer Boxes with the Folded Metal Corners.
Boxes fit into each other
2x 2mm holes to mount a Belt Clip.
2" x 3" x 1"
meets 501st requirements
"Two boxes shall be present on either side of buckle. Dimensions are approximately 2" (50.8mm) by 3" (76.2mm) by 1" (24.5mm)."
Amazon Basic PETG