Yes, 1/30,000 is faster than 1/25,000.
The other issue is how is it measured? Light to the 50% point, 60%, 80% dark?
There are lies, damn lies, and Chinese specifications
Odd, HomerD sells a Lincoln Electric auto helmet that boasts a 1/400 sec response time. Useless. I'll take my no-name 1/25000 over it any day (at half the price.)
I suppose they'll use a photo resistor of some type and shine a bright light of a certain lumen through the helmet to the photo resistor on the other side.
Then time it's reaction between the resistor voltage which will go high when the light hits it and the voltage drop when it goes dark. The time it takes for the resistor to react will be the mask reaction time.
Interestingly enough if i have done my maths correct, in that 1/25000 of a second your eyes will have absorbed 11km of light, or light will have travel that far in the time it has taken to change
Maybe, look it up on Google...