This is the warmest and most durable piece of handwear that OR makes. Palm material, shell fabric, and Velcro closures have all been enhanced to provide superior performance in the roughest conditions. It was designed to resist the wear and tear that would be inflicted by a professional mountain guide; far more abuse than normal weekend warriors would give it. The combination of modularity, durability, warmth, and a track record of use in big, cold country is unequaled in any other mitt. This one will get you there and back again with all your fingers intact. Professional Mitts accept the same three liners (Single, Double, and GT) as the Expedition Modular Mitt.