They set out for buried treasure on the pond's far side and returned with their water bottles full of pollywogs. Mission accomplished. The Patagonia Boy's Simple Synchilla Jacket is a classic day-to-day throw-on, the Simple SynchillaŽ Jacket uses 7.6-oz 100% polyester (85% recycled) double-faced fleece to keep intrepid, spontaneous adventurers warm and active. It has a full-zip front with an internal wind flap, zippered handwarmer pockets, a stand-up collar for warmth, and reflective collar patch and zipper pulls to keep them visible when quests segue into the gloaming. With a hand-me-down ID label inside.