medieval armor part 3d model

Create a precise, functional 3D model of a mechanical part with dark medieval armor style. CRITICAL: Maintain exact proportions. Do NOT redesign or deform. This must fit into another object. Dimensions: Height ≥ 4.2 cm Width ≈ 5.8 cm Depth ≈ 4.5 cm Shape: Rounded rectangular body (not spherical). Front: Centered rectangular cavity with rounded corners. Keep exact shape and proportions. Thick border around it. Sides: Cylindrical extensions on left and right, symmetric. Back: Curved surface with a circular hole (0.5 cm), slightly off-center. Constraints: Clean geometry, 3D printable, no extra elements affecting fit. Style: Dark medieval armor, subtle engravings only on surface. Do NOT modify structure. Goal: Functional part first, aesthetic second.