Seanwrote a review of Mountain Hardwear Masherbrum Mitten on November 21, 2008
I tried these out for an upcoming trip to Aconcagua. If I wasn't in the market for a mitten system (shell + liner) then I'd definitely pick these up. They're lofted full of warm insulation and fit amazingly well. They feel more dexterous than a 2-piece system since you don't have an inner mitten slipping around inside the outer shell. The gauntlets extend far and are large enough to get around he wrists of bulky parkas. I also liked the simple closure system and easily-adjustable wrist strap, something that seems to be missing from most of the other high altitude mittens out there which just have full elastic wrists.
MH claims on the packaging this is their warmest mitten and after trying it on I don't doubt that claim.