The Men's Absolute Mitt by Black Diamond. Black Diamond's warmest and lightest expedition mitt that will keep your hands warm and dry with minimal weight (liner can also serve as a really lightweight packable stash mitt for emergencies).
DECENT FEATURES of the Black Diamond Men's Absolute Mitt
100% waterproof and breathable Gore-Tex insert with XCR Product Technology stays with the shell
Pertex 15d ripstop shell
Removable liner is insulated with combination 85 g PrimaLoft Kodenshi and high-loft fleece
Outer mitt is insulated with 284 g PrimaLoft Kodenshi
Reinforced leather thumb adds durability for working with fixed lines
These are incredibly warm! One thing to note is that you will have pretty much no dexterity, although pretty much nothing that is this warm will have a lot of dexterity.