Our lens will darken long before that dangerous point. Faster helmets may choose switching time over better infrared protection. We think that's a dangerous compromise to make just to make a sale. Faster speeds may also mean a lower optical quality . If you can't see your work clearly, it doesn't matter how fast it darkens.
Infrared light is invisible and can be very dangerous.
In time, unprotected exposure to it can cause cataracts and blindness. It is the purple color you see on the outside of the lens. That is more protection than most lenses you'll ever use, plus you get the bonus of seeing the visible portion of the light spectrum as light as a shade 9 or as dark as 13. You don't have to spend a fortune to breathe clean, pure air while welding. This system is worn comfortably around the waist and works up to 8 hours on a battery pack charge.