The other thing that needs to be considered is accident performance whilst wearing goggles.
With the counterweights and goggles, the alpha helmet weighs in at 3kg.
The ONLY UK trials ever conducted by anyone, is the one with the mil looking at crashworthiness of NVG using an S61 in a simulated crash up to 25 'G's'.
God only knows what spec would need to be applied to civvy performance ratings.
But on the mil results alone, the human vertebrae would have to sustain acceleration forces, the equivalent of 75kg (165lbs)(12st) resting on your shoulders
And we haven't even begun to look at impact force from goggles.
Any views from experienced wearers????