An optical see-through augmented-reality module that retrofits onto an existing self-contained breathing apparatus (SCBA) full-face mask by replacing only the visor, meaning the front shield, and the upper visor holder. The existing mask body and face-seal geometry remain unchanged. The display system uses two 0.6-inch micro-OLED displays, each with 1920 x 1080 RGB resolution and a 44-degree field of view, coupled to near-eye optical assemblies. Because the architecture is optical see-through, the wearer views the floor and surroundings directly through the shield while digital content is displayed. Only the optical assemblies remain inside the mask; the processor and battery are relocated to an external top module, removing the primary heat sources from the sealed mask volume. For positioning in GPS-denied ship interiors, camera-based Visual-Inertial Odometry is fused with six-degree-of-freedom (6DoF) IMU dead reckoning, and the system targets sub-1 m RMS positioning accuracy.