Power Stretch pants can be very useful, and Rab's are well made, but there are two caveats.1. Rab's sizing and fit are different from those used by most brands sold in the US. I would not buy these without "Free Returns" option.2. Unlike Power Stretch tops, Power Stretch Pro pants are a very specialized piece of clothing. As a base layer, they are definitely not "lightweight". They are fairly thick, warm, provide considerable wind resistance, and they do not dry fast. They can be invaluable in high and moderate altitude mountaineering (as a base or the only layer), but I would never use them for skiing, hiking, or backpacking.Powerstretch come in Ladies sizes 12, 14, 16 etc and Men's S, M, L, XL. However, in our family we have purchased ladies 12, 14 and Men's Large and they have all had an identical size and cut in size and length when laid on top of each other, the same waistband elastic size etc! . It seems to be that the fabric simply stretches to fit, resulting in a much snugger fit on tall or larger waisted men, and a rather more relaxed fit on petite women.They are stretchy close fitting/skin tight but not over tight, warm, comfortable and fitted perfectly so sized correctly. They are strictly very cold weather leggings as they are so warm, I tend to use them for sleeping in to up rate my sleeping bag but wouldn't hesitate to walk in them when its cold enough as they are so comfortable and stretchy.Very robust, comfortable and warm. Normally used as outer layer.Love the fabric and the manufacturer. Bought mens as ladies too short in the body and leg. Med fits fine for a 14Excellent. So comfortable