Endoscopes
Endoscopes are what surgeons use in key hole surgery. When I bought my zeiss unit there were no cheaper alternatives like Hawks. All the aircraft engineers an alike were using them. With all the bells and whistles on it you can alter many aspects. Magnification, angle of view, color temperature of light and so on. Resolution wise they are an overkill for what we need. It cost a lot back in the '80s when I bought it. I don't take it to the range for fear someone drops a sandbag on it. Couldn't afford to replace it. That's why a bought an innovative technologies unit for that job.