I would challenge others to find a harsher environment than a TBM (Tunnel Boring Machine). We used cameras at multiple locations along the TBM to view progress and as indicators for material conveyance. These cameras were mounted beside conveyor belts which had hard rock tunneling waste transported at high speed past the camera. It was not uncommon for small and medium size rocks to hit these cameras on the lens and body. They stood up to this punishment 24/7 and the only thing replaced was the occasional protective glass on the camera enclosure. I would recommend these cameras for all harsh environment CCTV monitoring and surveillance. I believe the are virtually indestructible.