I have one Gen III tube and one Gen II image intensifiers for sale.
These have no blemishes and are in excelent working condition. Just add 3volt battery and go. The Gen III tube is very, very sensitive with 64 lpmm and the Gen II is around 45 to 50 lpmm. These came out of night vision gogles for use in Astronomy. The Gen III tube outperforms the Collins eyepiece, with about 55,000 gain. The Gen II tube has about 30-35,000 gain.
Both these tubes have adjustable gain and adjustable cathode
$1200 the Gen III or best.
$450 the Gen II or best.