Black performance baselayer in Patagonia's recycled polyester Capilene material. I think they're the midweight style, but I'm not 100% sure - it's an older style, so the style number isn't currently in use. Has seams (so not the air bottoms) and no fly (so likely not the thermal weight). In good used condition with no known flaws. Approximate measurements from flat lay: waist: 13.75" unstretched (very stretchy waistband!) rise: 12" inseam: 31"