I had a chance to use the Longevity auto dark helmet today and must say I am impressed. I was welding low amperage DC TIG which is a pretty good test of the light filtering hold on the helmet. Some helmets will open up on low amperage TIG briefly but not this one, it maintained the light filtering regardless of how low the current was set. I had the sensitivity on max and the delay on minimum.
I especially liked the solid lock on the helmet when raising the helmet up. It never slipped down while doing setup with it on.
I also used the unit when doing some stick welding and it worked perfectly on this as well.
My other helmet is a mid range HF unit and works ok but slips down while doing setup which is a pain. The HF unit is now going to be my backup unit, I like the Longevity unit much better.

Dan