Why are quad tube night vision devices illegal for civilians to own?

Night Vision tube manufacturers

They arenu2019t illegal to own, (at least in the US)but the manufactures have an exclusive contract to only sell to the governmentu2026 so itu2019s near impossible to buy them

AGM Global Vision

* FLIR Scout TK Mini (excellent small, mid-range thermal monocular)n * Pulsar Axion XM30 (top of the range thermal monocular u2013 expensive but still good value)n * AGM Glo.