The Patagonia Men's Nano Puff Pants are packable, breathable, low-bulk insulated pants for layering under waders in cold conditions. They're so comfortable and warm, even when wet, that you'll still be wearing them long after your waders are hung up to dry. The ultralight polyester shellwith a DWR (durable water repellent) finish and a reinforced seatslides easily in and out of waders. Elastic waistband and belt loops prevent unintentional moon sightings. Zip fly, front slash pockets and zippered rear security pocket provide easy access and storage.