The Q36. 5 Gregarius Winter Bib Tights pair a DWR-treated nylon exterior with a hydrophobic polyester interior, all in a tight-knit UF Thermo Plus fabric. Rainwater and road spray meet the exterior first, while the interior insulates and pulls moisture away from the skin on winter rides. What Our Gearhead(R) Experts Are Saying:"Nothing bunches behind my knees on long cold rides, because the pattern is cut for the pedaling position with very few seams. The saddle panel has no center seam, so I don't get a pressure line by hour three."