The Power supply also doubles up as the counterweight. The goggles draw power from the transformer in the back of the head(12-14V). Weighing in at 2.5Kgs they are lighter then they appear. The PNV-57E is a Gen 1+ Device designed for Helicopter, tank and Boat crew. The American equivalent to the PNV-57E would be the AN/PVS-5 night vision goggle. Ex-Polish PNV-57E Starlight Night vision goggles, are a evolutionary step up from the Active gen 0 PNV-57. At a price tag of $250(shipping from Poland is another story) I couldn't complain. I bought these more for collecting/curio and playing around with then for airsoft. Introducing the Personal Night vision 57E Gen 1+
