These mittens are an excellent part of a multi-layer handwear system. I've always liked unlined shell mittens for their versatility. These OR Endeavor mitts are windproof and waterproof, and can be worn with varying levels of insulation, which is critical for sports like backcountry skiing. For the skin up a slope, I wear Black Diamond Woolweight liners underneath these shells. If my hands get too warm, the shells can be removed and placed over my ski pole handles or stuffed in a jacket pocket. For the ski down, or other less aerobic activities, I'll wear them over Ortovox Dachstein boiled wool mitts for an extremely warm combination that still preserves some dexterity. They can also be worn alone for rain protection in warmer conditions. These shells are lightweight, but have proven to be plenty durable over many backcountry sessions so far. They're definitely not flimsy. The rubberized palms provide plenty of grip. I also like the simple cuff cord system -- pull the gray cordlock to tighten them, then pull the black cordlock to loosen when needed.

Best mitt shells out there. Tough and waterproof. Works well with wool interior gloves as mentioned. Palms are grippy.

These mitts round out my three piece backcountry glove system. I use them on the descent over the soft shell gloves I wear skinning up or over a pair of puffy mitts if it's super cold. They're lightweight and waterproof with a gauntlet over your sleeve and a great synching system. They stuff into a pocket and disappear. I'm not sure how paclight will stand up to a season of tree riding but you usually sacrafice abrasion resistance when you go for weight savings.