Ditto to those finding the HF auto dark helmet is a great tool at a great price. My worst problem with mine is when I pull it down low enough to look through my bifocals I smear nose oil on the inside of the view port. I like the solar charger feature and never need (except for the initial charge) to put it out in the sun to charge it. It seems to do OK on the light level in my metal working shop, even in winter.
Oh, I added a leather neck guard to the "chin" of the helmet as I was getting arc burn on my neck. totally fixed the problem.
Mine is the BLUE FLAME model as well. I have had two "HIGH END" auto dark helmets before that were given to me and I gave one away and the one I kept died. The HF blue flame special works better than the other two did and I don't have to change batteries.
I left it out in the rain and while it was wet it didn't work right. After it dried out it has worked just fine (for a year at least since it was in rain.)
A product improvement suggestion would be to add a detent to the darkening control knob which was an OFF position to prevent auto darkening. This would have two benefits: 1. You could wear the helmet while grinding and not have the sparks make the helmet blink on and off preventing your ability to see what you are grinding and 2. the shade #4 when it is not auto darkening is good for plasma cutting but... the sparks make it auto darken which obscures your view.
Pat