From the REI Website:
Taku Pants offer the ultimate in versatility—with waterproof, breathable and lightweight stretch comfort.
A great selection for aerobic activities in cold conditions when you may encounter windy, wet weather; think climbing, snowshoeing and spring skiing
Also from the REI Website:
Athletic, close-fitting cut is thermally efficient and doesn't inhibit movement
Front lower legs and upper posterior region are made from a 3-layer laminated nylon fabric offering waterproof, breathable protection and durability
Upper front legs and rear lower legs are a waterproof, soft shell laminate offering comfortable four-way stretch, high mobility and breathability
All seams are sealed for weather-tight protection
Thigh vents allow air movement and help regulate body temperature
Comfortable articulated legs allow full range of motion
Features two welded (glued) hand pockets with water-resistant zippers; and a zippered rear pocket
Removable, internal back elastic belt adjusts waist circumference with rubber grips and hook-and-loop tabs at each side
Features soft, brushed tricot-lined back waistband that wicks away moisture; front fly
Lower-leg zippers are designed with three-inch wide gussets to fit over a variety of boot widths
Hem drawcords cinch down securely over boots
Windproof to 60 mph
I was hesitant to get these pants because they didn't really fall within my "ultralight" ethos at 19 ounces, but I figured if I could avoid bringing rain shells and just wear these, it might just work out.
My first experience with these pants was in Switzerland snowshoeing across the Aletsche Glacier. Day 1: Nearly 65+ degrees, without taking into account the heat shining off the glacier. In other words: HOT! Even in just a T-shirt I was sweating. These pants breathed amazingly well and kept my legs cool. The only place I started to get sweaty was my below my knee, and that was due to having my gators on. Day 2: 6:00am. Low 30's/ high 20's with a freezing wind (I wiped my nose on my glove and it froze within 30 seconds!). These pants blocked the wind, and even with just a light pair of Capilene underneath, kept my legs warm.
To say the least, I was impressed with the variance of conditions these pants showed with breathability. Also, the waist is easy to adjust with glove and, even without an underlayer on, the pants and comfortable. The articulated knees allow for easy movement, and the thigh vents are key to the ventilation. I cannot speak for their resistance to rain, as I have not experienced it. (Sorry!)
With other pants with similar features stretching over $200, these pants are a good deal.