Hey THWACK -
I just bought one of those muffs last night & tried it out this AM in -5 windchill - ambient was 6.
That thing is fantastic man! Wow - toasty warm. I was able to use my super thin half gloves & was even able to have the bow release inside keeping warm as well.
Would not trade it for anything. I'd say that it'll keep my ahnds warm down to at least -20, perhaps more. Question is - do I want to hunt in -20?
"It's not the kill, it's the adventure and challenge! <img src=icon_smile_big.gif border=0 align=middle>"