Case 1: 100% Polyester. Shell 2: 88% Polyester, 12% Elastane. Fill: 100% Polyester. The Thermal Insulation Long Shorts W are a pair of longer hybrid shorts with a lightly padded front. Four-way stretch on the side and at the kneesWindproof, padded panelingPFC-free, water repellent outer fabricThe padded longer shorts have four-way stretch on the back and a light padding on the front to keep you warm. The outer fabric is woven together which makes the garment very exclusive. Works great as a mid-layer under the shell pants to keep the heat on the thighs, or wear the shorts over a pair of base layer pants during running training in the colder temperatures.