Guess I won't be looking at the sun :)
I don't mean to say that people shouldn't take safety seriously - just saying that it's interesting how we used homemade solution to this and don't have any (obvious) sight problems.
arc welding gear is generally around 10-11.
many newer electronic helmets go up to 13/14 which is enough, you have to remember to turn up the sensitivity on the sensors so that its always dark. otherwise it will stay open at around 3-4
And it may happen to be that blocking the visual with the counterfeits also blocks the invisible wavelengths. Or it may not.
There should be some statistical evidence provided.
I did read from one of the recommended manufacturers that they tried to warn Amazon about this for months. They also tested them and they appeared safe in the tests they ran even though they were not legitimate.
But only Amazon knows what they have actually sold.
Be careful!