Carhartt's sandstone duck bib overalls will keep you warm all day. Made of 12-ounce, 100-percent sandstone duck, they lined with a midweight, 100-percent quilted nylon polyester.They feature double knees with cleanout bottoms to accommodate knee pads and have zip-to-knee leg openings with a protective wind flap. They also has several tool and utility pockets, a hammer loop and brush loop. Back pockets are reinforced for durability.